{"id":80175,"date":"2024-10-21T16:47:59","date_gmt":"2024-10-21T09:47:59","guid":{"rendered":"https:\/\/itviec.com\/blog\/?p=80175"},"modified":"2024-10-21T16:47:59","modified_gmt":"2024-10-21T09:47:59","slug":"cau-hoi-phong-van-oop-phan-1","status":"publish","type":"post","link":"https:\/\/itviec.com\/blog\/cau-hoi-phong-van-oop-phan-1\/","title":{"rendered":"Top 50+ c\u00e2u h\u1ecfi ph\u1ecfng v\u1ea5n OOP v\u00e0 tr\u1ea3 l\u1eddi m\u1edbi nh\u1ea5t (Ph\u1ea7n 1)"},"content":{"rendered":"<div id=\"ez-toc-container\" class=\"ez-toc-v2_0_84 counter-hierarchy ez-toc-counter ez-toc-grey ez-toc-container-direction\">\n<div class=\"ez-toc-title-container\">\n<p class=\"ez-toc-title\" style=\"cursor:inherit\">N\u1ed9i dung b\u00e0i vi\u1ebft<\/p>\n<span class=\"ez-toc-title-toggle\"><a href=\"#\" class=\"ez-toc-pull-right ez-toc-btn ez-toc-btn-xs ez-toc-btn-default ez-toc-toggle\" aria-label=\"Toggle Table of Content\"><span class=\"ez-toc-js-icon-con\"><span class=\"\"><span class=\"eztoc-hide\" style=\"display:none;\">Toggle<\/span><span class=\"ez-toc-icon-toggle-span\"><svg style=\"fill: #999;color:#999\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\" class=\"list-377408\" width=\"20px\" height=\"20px\" viewBox=\"0 0 24 24\" fill=\"none\"><path d=\"M6 6H4v2h2V6zm14 0H8v2h12V6zM4 11h2v2H4v-2zm16 0H8v2h12v-2zM4 16h2v2H4v-2zm16 0H8v2h12v-2z\" fill=\"currentColor\"><\/path><\/svg><svg style=\"fill: #999;color:#999\" class=\"arrow-unsorted-368013\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\" width=\"10px\" height=\"10px\" viewBox=\"0 0 24 24\" version=\"1.2\" baseProfile=\"tiny\"><path d=\"M18.2 9.3l-6.2-6.3-6.2 6.3c-.2.2-.3.4-.3.7s.1.5.3.7c.2.2.4.3.7.3h11c.3 0 .5-.1.7-.3.2-.2.3-.5.3-.7s-.1-.5-.3-.7zM5.8 14.7l6.2 6.3 6.2-6.3c.2-.2.3-.5.3-.7s-.1-.5-.3-.7c-.2-.2-.4-.3-.7-.3h-11c-.3 0-.5.1-.7.3-.2.2-.3.5-.3.7s.1.5.3.7z\"\/><\/svg><\/span><\/span><\/span><\/a><\/span><\/div>\n<nav><ul class='ez-toc-list ez-toc-list-level-1 ' ><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-1\" href=\"https:\/\/itviec.com\/blog\/cau-hoi-phong-van-oop-phan-1\/#OOP_la_gi\" >OOP l\u00e0 g\u00ec?<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-2\" href=\"https:\/\/itviec.com\/blog\/cau-hoi-phong-van-oop-phan-1\/#Cac_cau_hoi_phong_van_OOP_cap_do_Fresher\" >C\u00e1c c\u00e2u h\u1ecfi ph\u1ecfng v\u1ea5n OOP c\u1ea5p \u0111\u1ed9 Fresher<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-3\" href=\"https:\/\/itviec.com\/blog\/cau-hoi-phong-van-oop-phan-1\/#Cac_cau_hoi_phong_van_OOP_cap_do_Junior_Developer\" >C\u00e1c c\u00e2u h\u1ecfi ph\u1ecfng v\u1ea5n OOP c\u1ea5p \u0111\u1ed9 Junior Developer<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-4\" href=\"https:\/\/itviec.com\/blog\/cau-hoi-phong-van-oop-phan-1\/#Tong_ket_Cau_hoi_phong_van_OOP_Phan_1\" >T\u1ed5ng k\u1ebft C\u00e2u h\u1ecfi ph\u1ecfng v\u1ea5n OOP (Ph\u1ea7n 1)<\/a><\/li><\/ul><\/nav><\/div>\n<p><b><i>L\u1eadp tr\u00ecnh h\u01b0\u1edbng \u0111\u1ed1i t\u01b0\u1ee3ng (OOP) l\u00e0 m\u1ed9t trong nh\u1eefng k\u1ef9 n\u0103ng c\u1ed1t l\u00f5i m\u00e0 c\u00e1c Software Developer c\u1ea7n ph\u1ea3i n\u1eafm v\u1eefng. \u0110\u1ec3 \u0111\u00e1nh gi\u00e1 k\u1ef9 n\u0103ng OOP c\u1ee7a \u1ee9ng vi\u00ean, c\u00e1c nh\u00e0 tuy\u1ec3n d\u1ee5ng th\u01b0\u1eddng \u0111\u01b0a ra nh\u1eefng c\u00e2u h\u1ecfi ph\u1ecfng v\u1ea5n r\u1ea5t \u0111a d\u1ea1ng. H\u00e3y c\u00f9ng ITviec kh\u00e1m ph\u00e1 50 c\u00e2u h\u1ecfi ph\u1ecfng v\u1ea5n OOP th\u01b0\u1eddng g\u1eb7p nh\u1ea5t hi\u1ec7n nay c\u00f9ng c\u00e2u tr\u1ea3 l\u1eddi chu\u1ea9n x\u00e1c. T\u1eeb nh\u1eefng kh\u00e1i ni\u1ec7m c\u01a1 b\u1ea3n \u0111\u1ebfn nh\u1eefng v\u1ea5n \u0111\u1ec1 n\u00e2ng cao, ch\u00fang t\u00f4i s\u1ebd gi\u00fap b\u1ea1n n\u1eafm v\u1eefng ki\u1ebfn th\u1ee9c OOP v\u00e0 th\u00e0nh c\u00f4ng trong c\u00e1c bu\u1ed5i ph\u1ecfng v\u1ea5n. Ph\u1ea7n 1 trong b\u00e0i vi\u1ebft n\u00e0y s\u1ebd l\u00e0 nh\u1eefng c\u00e2u h\u1ecfi ph\u1ecfng v\u1ea5n OOP c\u1ea5p \u0111\u1ed9 \u0111\u1ea7u v\u00e0o.<\/i><\/b><\/p>\n<p><span style=\"font-weight: 400;\">Trong Ph\u1ea7n 1, h\u00e3y c\u00f9ng t\u00ecm hi\u1ec3u v\u1ec1:<\/span><\/p>\n<ul>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">OOP l\u00e0 g\u00ec<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">25 c\u00e2u h\u1ecfi ph\u1ecfng v\u1ea5n OOP c\u1ea5p \u0111\u1ed9 \u0111\u1ea7u v\u00e0o (Fresher\/ Junior Developer) k\u00e8m c\u00e2u tr\u1ea3 l\u1eddi chi ti\u1ebft<\/span><\/li>\n<\/ul>\n<blockquote><p><em>N\u1ebfu b\u1ea1n \u0111ang chu\u1ea9n b\u1ecb cho c\u00e1c v\u1ecb tr\u00ed Middle\/ Senior Developer ho\u1eb7c t\u00ecm ki\u1ebfm nh\u1eefng c\u00e2u h\u1ecfi ph\u1ecfng v\u1ea5n OOP th\u1ef1c h\u00e0nh, b\u1ea1n c\u00f3 th\u1ec3 tham kh\u1ea3o <a href=\"https:\/\/itviec.com\/blog\/cau-hoi-phong-van-oop-phan-2\/\" target=\"_blank\" rel=\"noopener\"><strong>Ph\u1ea7n 2<\/strong><\/a> c\u1ee7a C\u00e1c c\u00e2u h\u1ecfi ph\u1ecfng v\u1ea5n OOP.<\/em><\/p><\/blockquote>\n<h2><span class=\"ez-toc-section\" id=\"OOP_la_gi\"><\/span><b> OOP l\u00e0 g\u00ec?<\/b><span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p><span style=\"font-weight: 400;\">Object-oriented programming (OOP) hay c\u00f2n g\u1ecdi l\u1eadp tr\u00ecnh h\u01b0\u1edbng \u0111\u1ed1i t\u01b0\u1ee3ng l\u00e0 m\u1ed9t m\u00f4 h\u00ecnh l\u1eadp tr\u00ecnh m\u00e1y t\u00ednh t\u1ed5 ch\u1ee9c thi\u1ebft k\u1ebf ph\u1ea7n m\u1ec1m xung quanh d\u1eef li\u1ec7u (data) ho\u1eb7c \u0111\u1ed1i t\u01b0\u1ee3ng (object), thay v\u00ec c\u00e1c h\u00e0m v\u00e0 logic. \u0110\u1ed1i t\u01b0\u1ee3ng c\u00f3 th\u1ec3 \u0111\u01b0\u1ee3c \u0111\u1ecbnh ngh\u0129a l\u00e0 m\u1ed9t tr\u01b0\u1eddng d\u1eef li\u1ec7u c\u00f3 c\u00e1c thu\u1ed9c t\u00ednh v\u00e0 h\u00e0nh vi duy nh\u1ea5t.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">OOP t\u1eadp trung v\u00e0o c\u00e1c object m\u00e0 Developer mu\u1ed1n thao t\u00e1c thay v\u00ec logic c\u1ea7n thi\u1ebft \u0111\u1ec3 thao t\u00e1c ch\u00fang. C\u00e1ch ti\u1ebfp c\u1eadn l\u1eadp tr\u00ecnh n\u00e0y r\u1ea5t ph\u00f9 h\u1ee3p v\u1edbi ph\u1ea7n m\u1ec1m l\u1edbn, ph\u1ee9c t\u1ea1p v\u00e0 \u0111\u01b0\u1ee3c c\u1eadp nh\u1eadt ho\u1eb7c b\u1ea3o tr\u00ec t\u00edch c\u1ef1c. \u0110i\u1ec1u n\u00e0y bao g\u1ed3m c\u00e1c ch\u01b0\u01a1ng tr\u00ecnh s\u1ea3n xu\u1ea5t v\u00e0 thi\u1ebft k\u1ebf, c\u0169ng nh\u01b0 c\u00e1c \u1ee9ng d\u1ee5ng di \u0111\u1ed9ng.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">V\u00ed d\u1ee5, OOP c\u00f3 th\u1ec3 \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng cho ph\u1ea7n m\u1ec1m m\u00f4 ph\u1ecfng h\u1ec7 th\u1ed1ng s\u1ea3n xu\u1ea5t. Ph\u01b0\u01a1ng ph\u00e1p n\u00e0y c\u00f3 l\u1ee3i cho ph\u00e1t tri\u1ec3n c\u1ed9ng t\u00e1c, trong \u0111\u00f3 c\u00e1c d\u1ef1 \u00e1n \u0111\u01b0\u1ee3c chia th\u00e0nh c\u00e1c nh\u00f3m. C\u00e1c l\u1ee3i \u00edch b\u1ed5 sung c\u1ee7a OOP bao g\u1ed3m kh\u1ea3 n\u0103ng t\u00e1i s\u1eed d\u1ee5ng m\u00e3, kh\u1ea3 n\u0103ng m\u1edf r\u1ed9ng v\u00e0 hi\u1ec7u qu\u1ea3.<\/span><\/p>\n<blockquote><p><em>\u0110\u1ecdc th\u00eam: <a href=\"https:\/\/itviec.com\/blog\/oop-la-gi\/\" target=\"_blank\" rel=\"noopener\"><strong>OOP l\u00e0 g\u00ec? 4 \u0111\u1eb7c t\u00ednh c\u01a1 b\u1ea3n c\u1ee7a OOP<\/strong><\/a><\/em><\/p><\/blockquote>\n<h2><span class=\"ez-toc-section\" id=\"Cac_cau_hoi_phong_van_OOP_cap_do_Fresher\"><\/span><b> C\u00e1c c\u00e2u h\u1ecfi ph\u1ecfng v\u1ea5n OOP c\u1ea5p \u0111\u1ed9 Fresher<\/b><span class=\"ez-toc-section-end\"><\/span><\/h2>\n<h3><b> OOP l\u00e0 g\u00ec?<\/b><\/h3>\n<p><span style=\"font-weight: 400;\">OOP l\u00e0 ph\u01b0\u01a1ng ph\u00e1p l\u1eadp tr\u00ecnh s\u1eed d\u1ee5ng c\u00e1c class v\u00e0 object \u0111\u1ec3 t\u1ed5 ch\u1ee9c c\u00e1c ch\u01b0\u01a1ng tr\u00ecnh ph\u1ea7n m\u1ec1m th\u00e0nh c\u00e1c m\u1eabu code c\u00f3 th\u1ec3 t\u00e1i s\u1eed d\u1ee5ng.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">C\u00e1c ng\u00f4n ng\u1eef nh\u01b0 Java, C++, Python v\u00e0 JavaScript h\u1ed7 tr\u1ee3 OOP b\u1eb1ng c\u00e1ch t\u1ea1o \u0111i\u1ec1u ki\u1ec7n thu\u1eadn l\u1ee3i cho vi\u1ec7c t\u1ea1o c\u00e1c class ch\u1ec9 \u0111\u1ecbnh c\u00e1c thu\u1ed9c t\u00ednh v\u00e0 ph\u01b0\u01a1ng th\u1ee9c, trong khi c\u00e1c object l\u00e0 th\u1ec3 hi\u1ec7n c\u1ee7a c\u00e1c class n\u00e0y. C\u00e1c nguy\u00ean t\u1eafc OOP bao g\u1ed3m k\u1ebf th\u1eeba, \u0111\u00f3ng g\u00f3i, \u0111a h\u00ecnh v\u00e0 tr\u1eebu t\u01b0\u1ee3ng h\u00f3a, t\u1ea1o \u0111i\u1ec1u ki\u1ec7n thu\u1eadn l\u1ee3i cho vi\u1ec7c th\u1ec3 hi\u1ec7n c\u00e1c th\u1ef1c th\u1ec3 trong th\u1ebf gi\u1edbi th\u1ef1c c\u1ee7a thi\u1ebft k\u1ebf ph\u1ea7n m\u1ec1m.<\/span><\/p>\n<h3><b>Li\u1ec7t k\u00ea c\u00e1c ng\u00f4n ng\u1eef l\u1eadp tr\u00ecnh h\u01b0\u1edbng \u0111\u1ed1i t\u01b0\u1ee3ng ch\u00ednh<\/b><\/h3>\n<p><span style=\"font-weight: 400;\">C\u00e1c ng\u00f4n ng\u1eef l\u1eadp tr\u00ecnh s\u1eed d\u1ee5ng v\u00e0 tu\u00e2n theo m\u00f4 h\u00ecnh OOP \u0111\u01b0\u1ee3c g\u1ecdi l\u00e0 ng\u00f4n ng\u1eef l\u1eadp tr\u00ecnh h\u01b0\u1edbng \u0111\u1ed1i t\u01b0\u1ee3ng. M\u1ed9t s\u1ed1 ng\u00f4n ng\u1eef l\u1eadp tr\u00ecnh h\u01b0\u1edbng \u0111\u1ed1i t\u01b0\u1ee3ng ch\u00ednh bao g\u1ed3m:<\/span><\/p>\n<ul>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">Java<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">C++<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">Javascript<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">Python<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">PHP<\/span><\/li>\n<\/ul>\n<h3><b>T\u1ea1i sao c\u1ea7n OOP?<\/b><\/h3>\n<p><span style=\"font-weight: 400;\">OOP c\u1ea7n s\u1eed d\u1ee5ng b\u1edfi c\u00e1c l\u1ee3i \u00edch:<\/span><\/p>\n<ul>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">T\u00ednh m\u00f4-\u0111un: OOP th\u00fac \u0111\u1ea9y thi\u1ebft k\u1ebf m\u00f4-\u0111un, gi\u00fap chia c\u00e1c v\u1ea5n \u0111\u1ec1 ph\u1ee9c t\u1ea1p th\u00e0nh c\u00e1c ph\u1ea7n nh\u1ecf h\u01a1n, d\u1ec5 qu\u1ea3n l\u00fd h\u01a1n.<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">Kh\u1ea3 n\u0103ng t\u00e1i s\u1eed d\u1ee5ng: V\u1edbi OOP, b\u1ea1n c\u00f3 th\u1ec3 s\u1eed d\u1ee5ng c\u00e1c class v\u00e0 object nhi\u1ec1u l\u1ea7n \u1edf c\u00e1c ph\u1ea7n kh\u00e1c nhau c\u1ee7a ch\u01b0\u01a1ng tr\u00ecnh ho\u1eb7c c\u00e1c ch\u01b0\u01a1ng tr\u00ecnh kh\u00e1c, gi\u00fap ti\u1ebft ki\u1ec7m th\u1eddi gian v\u00e0 l\u00e0m cho ch\u01b0\u01a1ng tr\u00ecnh hi\u1ec7u qu\u1ea3 h\u01a1n.<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">\u0110\u00f3ng g\u00f3i: \u0110\u00f3ng g\u00f3i \u1ea9n \u0111i ho\u1ea1t \u0111\u1ed9ng b\u00ean trong c\u1ee7a m\u1ed9t object v\u00e0 ch\u1ec9 hi\u1ec3n th\u1ecb nh\u1eefng g\u00ec c\u1ea7n thi\u1ebft, gi\u00fap m\u1ecdi th\u1ee9 \u0111\u01b0\u1ee3c an to\u00e0n v\u00e0 ng\u0103n ng\u1eeba nh\u1eefng thay \u0111\u1ed5i v\u00f4 t\u00ecnh.<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">K\u1ebf th\u1eeba: OOP cho ph\u00e9p b\u1ea1n t\u1ea1o c\u00e1c class m\u1edbi d\u1ef1a tr\u00ean c\u00e1c class hi\u1ec7n c\u00f3, gi\u00fap t\u00e1i s\u1eed d\u1ee5ng code v\u00e0 x\u00e2y d\u1ef1ng c\u00e1c m\u1ed1i quan h\u1ec7 c\u00f3 t\u1ed5 ch\u1ee9c gi\u1eefa c\u00e1c class.<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">\u0110a h\u00ecnh: OOP cho ph\u00e9p c\u00e1c object kh\u00e1c nhau \u0111\u01b0\u1ee3c coi nh\u01b0 thu\u1ed9c c\u00f9ng m\u1ed9t nh\u00f3m, gi\u00fap ph\u1ea7n m\u1ec1m linh ho\u1ea1t h\u01a1n v\u00e0 d\u1ec5 m\u1edf r\u1ed9ng h\u01a1n.<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">Tr\u1eebu t\u01b0\u1ee3ng h\u00f3a: OOP \u0111\u01a1n gi\u1ea3n h\u00f3a c\u00e1c \u0111\u1ed1i t\u01b0\u1ee3ng trong th\u1ebf gi\u1edbi th\u1ef1c th\u00e0nh c\u00e1c m\u00f4 h\u00ecnh d\u1ec5 hi\u1ec3u h\u01a1n, t\u1eadp trung v\u00e0o nh\u1eefng y\u1ebfu t\u1ed1 c\u1ea7n thi\u1ebft v\u00e0 \u1ea9n \u0111i c\u00e1c chi ti\u1ebft kh\u00f4ng c\u1ea7n thi\u1ebft.<\/span><\/li>\n<\/ul>\n<h3><b>Li\u1ec7t k\u00ea l\u1ee3i th\u1ebf c\u1ee7a vi\u1ec7c s\u1eed d\u1ee5ng OOP<\/b><\/h3>\n<ul>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">OOP r\u1ea5t h\u1eefu \u00edch trong vi\u1ec7c gi\u1ea3i quy\u1ebft nh\u1eefng v\u1ea5n \u0111\u1ec1 ph\u1ee9c t\u1ea1p.<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">C\u00e1c ch\u01b0\u01a1ng tr\u00ecnh c\u1ef1c k\u1ef3 ph\u1ee9c t\u1ea1p c\u00f3 th\u1ec3 \u0111\u01b0\u1ee3c t\u1ea1o, x\u1eed l\u00fd v\u00e0 b\u1ea3o tr\u00ec d\u1ec5 d\u00e0ng b\u1eb1ng c\u00e1ch s\u1eed d\u1ee5ng l\u1eadp tr\u00ecnh h\u01b0\u1edbng \u0111\u1ed1i t\u01b0\u1ee3ng.<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">OOP th\u00fac \u0111\u1ea9y vi\u1ec7c t\u00e1i s\u1eed d\u1ee5ng m\u00e3, do \u0111\u00f3 gi\u1ea3m thi\u1ec3u s\u1ef1 tr\u00f9ng l\u1eb7p.<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">OOP c\u0169ng gi\u00fap \u1ea9n \u0111i nh\u1eefng chi ti\u1ebft kh\u00f4ng c\u1ea7n thi\u1ebft v\u1edbi s\u1ef1 tr\u1ee3 gi\u00fap c\u1ee7a Tr\u1eebu t\u01b0\u1ee3ng h\u00f3a d\u1eef li\u1ec7u.<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">\u0110a h\u00ecnh mang l\u1ea1i nhi\u1ec1u t\u00ednh linh ho\u1ea1t trong OOP.<\/span><\/li>\n<\/ul>\n<h3><b> T\u1ea1i sao OOP l\u1ea1i ph\u1ed5 bi\u1ebfn?<\/b><\/h3>\n<p><span style=\"font-weight: 400;\">M\u00f4 h\u00ecnh l\u1eadp tr\u00ecnh OOP \u0111\u01b0\u1ee3c xem l\u00e0 m\u1ed9t phong c\u00e1ch l\u1eadp tr\u00ecnh t\u1ed1t h\u01a1n. OOP kh\u00f4ng ch\u1ec9 gi\u00fap vi\u1ebft m\u1ed9t \u0111o\u1ea1n m\u00e3 ph\u1ee9c t\u1ea1p tr\u1edf n\u00ean \u0111\u01a1n gi\u1ea3n m\u00e0 c\u00f2n cho ph\u00e9p ng\u01b0\u1eddi d\u00f9ng x\u1eed l\u00fd v\u00e0 b\u1ea3o tr\u00ec ch\u00fang m\u1ed9t c\u00e1ch d\u1ec5 d\u00e0ng. Kh\u00f4ng ch\u1ec9 v\u1eady, 4 t\u00ednh n\u0103ng ch\u00ednh c\u1ee7a OOP &#8211; Tr\u1eebu t\u01b0\u1ee3ng h\u00f3a d\u1eef li\u1ec7u, \u0110\u00f3ng g\u00f3i, K\u1ebf th\u1eeba v\u00e0 \u0110a h\u00ecnh, gi\u00fap c\u00e1c l\u1eadp tr\u00ecnh vi\u00ean d\u1ec5 d\u00e0ng gi\u1ea3i quy\u1ebft c\u00e1c t\u00ecnh hu\u1ed1ng ph\u1ee9c t\u1ea1p. Theo th\u1eddi gian, OOP tr\u1edf n\u00ean ph\u1ed5 bi\u1ebfn h\u01a1n.<\/span><\/p>\n<h3><b> C\u00e1c \u0111\u1eb7c \u0111i\u1ec3m c\u01a1 b\u1ea3n c\u1ee7a OOP l\u00e0 g\u00ec?<\/b><\/h3>\n<p><span style=\"font-weight: 400;\">C\u00e1c t\u00ednh n\u0103ng c\u01a1 b\u1ea3n c\u1ee7a OOP l\u00e0:<\/span><\/p>\n<ul>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">T\u00ednh \u0111\u00f3ng g\u00f3i (Encapsulation)<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">T\u00ednh k\u1ebf th\u1eeba (Inheritance)<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">T\u00ednh \u0111a h\u00ecnh (Polymorphism)<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">T\u00ednh tr\u1eebu t\u01b0\u1ee3ng (Abstraction).<\/span><\/li>\n<\/ul>\n<h3><b> Gi\u1ea3i th\u00edch kh\u00e1i ni\u1ec7m t\u00ednh k\u1ebf th\u1eeba b\u1eb1ng v\u00ed d\u1ee5 th\u1ef1c t\u1ebf<\/b><\/h3>\n<p><span style=\"font-weight: 400;\">Parent class l\u00e0 m\u1ed9t kh\u00e1i ni\u1ec7m logic, ch\u1eb3ng h\u1ea1n nh\u01b0 vehicle l\u00e0 base class x\u00e1c \u0111\u1ecbnh c\u00e1c thu\u1ed9c t\u00ednh chung \u0111\u01b0\u1ee3c chia s\u1ebb b\u1edfi t\u1ea5t c\u1ea3 c\u00e1c vehicle. Tuy nhi\u00ean, c\u00e1c subclass l\u00e0 m\u1ed9t lo\u1ea1i class c\u1ee5 th\u1ec3 h\u01a1n nh\u01b0 xe t\u1ea3i, xe bu\u00fdt, \u00f4 t\u00f4\u2026 K\u1ebf th\u1eeba cho ph\u00e9p c\u00e1c subclass k\u1ebf th\u1eeba c\u00e1c thu\u1ed9c t\u00ednh chung c\u1ee7a m\u1ed9t vehicle v\u00e0 x\u00e1c \u0111\u1ecbnh c\u00e1c thu\u1ed9c t\u00ednh v\u00e0 ph\u01b0\u01a1ng th\u1ee9c c\u1ee5 th\u1ec3 cho ri\u00eang ch\u00fang.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">V\u00ed d\u1ee5 b\u1eb1ng code Java:<\/span><\/p>\n<pre><span style=\"font-weight: 400;\">\/\/ L\u1edbp cha Vehicle (Ph\u01b0\u01a1ng ti\u1ec7n)<\/span>\r\n<span style=\"font-weight: 400;\">class Vehicle {<\/span>\r\n<span style=\"font-weight: 400;\"> \u00a0\u00a0\u00a0String color;<\/span>\r\n<span style=\"font-weight: 400;\"> \u00a0\u00a0\u00a0int numberOfWheels;<\/span>\r\n\r\n<span style=\"font-weight: 400;\">\u00a0\u00a0\u00a0\u00a0void move() {<\/span>\r\n<span style=\"font-weight: 400;\"> \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0System.out.println(\"Ph\u01b0\u01a1ng ti\u1ec7n \u0111ang di chuy\u1ec3n\");<\/span>\r\n<span style=\"font-weight: 400;\"> \u00a0\u00a0\u00a0}<\/span>\r\n<span style=\"font-weight: 400;\">}<\/span>\r\n\r\n<span style=\"font-weight: 400;\">\/\/ L\u1edbp con Car (\u00d4 t\u00f4) k\u1ebf th\u1eeba t\u1eeb Vehicle<\/span>\r\n<span style=\"font-weight: 400;\">class Car extends Vehicle {<\/span>\r\n<span style=\"font-weight: 400;\"> \u00a0\u00a0\u00a0int numberOfDoors;<\/span>\r\n\r\n<span style=\"font-weight: 400;\">\u00a0\u00a0\u00a0\u00a0void honk() {<\/span>\r\n<span style=\"font-weight: 400;\"> \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0System.out.println(\"T\u00fat t\u00fat\");<\/span>\r\n<span style=\"font-weight: 400;\"> \u00a0\u00a0\u00a0}<\/span>\r\n<span style=\"font-weight: 400;\">}<\/span>\r\n\r\n<span style=\"font-weight: 400;\">\/\/ L\u1edbp con Truck (Xe t\u1ea3i) k\u1ebf th\u1eeba t\u1eeb Vehicle<\/span>\r\n<span style=\"font-weight: 400;\">class Truck extends Vehicle {<\/span>\r\n<span style=\"font-weight: 400;\"> \u00a0\u00a0\u00a0int loadCapacity; \/\/ Kh\u1ea3 n\u0103ng t\u1ea3i<\/span>\r\n<span style=\"font-weight: 400;\">}<\/span><\/pre>\n<h3><b> C\u00e1c lo\u1ea1i Inheritance (k\u1ebf th\u1eeba) trong OOP<\/b><\/h3>\n<ul>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">Single Inheritance (k\u1ebf th\u1eeba \u0111\u01a1n): Subclass \u0111\u01b0\u1ee3c k\u1ebf th\u1eeba tr\u1ef1c ti\u1ebfp t\u1eeb base class.<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">Multiple Inheritance (k\u1ebf th\u1eeba \u0111a l\u1edbp): M\u1ed9t subclass k\u1ebf th\u1eeba t\u1eeb nhi\u1ec1u base class.<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">Multi-level Inheritance (k\u1ebf th\u1eeba \u0111a c\u1ea5p): Subclass \u0111\u01b0\u1ee3c k\u1ebf th\u1eeba t\u1eeb parent class, parent class l\u1ea1i \u0111\u01b0\u1ee3c k\u1ebf th\u1eeba t\u1eeb m\u1ed9t class kh\u00e1c.<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">Multi-path Inheritance (k\u1ebf th\u1eeba \u0111a \u0111\u01b0\u1eddng d\u1eabn): M\u1ed9t subclass k\u1ebf th\u1eeba t\u1eeb hai ho\u1eb7c nhi\u1ec1u l\u1edbp c\u00f3 m\u1ed9t base class chu\u1ea9n.<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">Hierarchical Inheritance (k\u1ebf th\u1eeba ph\u00e2n c\u1ea5p): Nhi\u1ec1u class k\u1ebf th\u1eeba \u0111\u01b0\u1ee3c t\u1ea1o ra t\u1eeb m\u1ed9t base class duy nh\u1ea5t.<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">Hybrid Inheritance (di truy\u1ec1n lai): S\u1ef1 k\u1ebft h\u1ee3p c\u1ee7a hai ho\u1eb7c nhi\u1ec1u lo\u1ea1i k\u1ebf th\u1eeba.<\/span><\/li>\n<\/ul>\n<h3><b> Encapsulation (t\u00ednh \u0111\u00f3ng g\u00f3i) l\u00e0 g\u00ec?<\/b><\/h3>\n<p><span style=\"font-weight: 400;\">T\u00ednh \u0111\u00f3ng g\u00f3i l\u00e0 s\u1ef1 li\u00ean k\u1ebft d\u1eef li\u1ec7u v\u00e0 c\u00e1c ph\u01b0\u01a1ng ph\u00e1p x\u1eed l\u00fd ch\u00fang th\u00e0nh m\u1ed9t \u0111\u01a1n v\u1ecb duy nh\u1ea5t sao cho d\u1eef li\u1ec7u nh\u1ea1y c\u1ea3m \u0111\u01b0\u1ee3c \u1ea9n kh\u1ecfi ng\u01b0\u1eddi d\u00f9ng. T\u00ednh \u0111\u00f3ng g\u00f3i \u0111\u01b0\u1ee3c tri\u1ec3n khai theo c\u00e1c quy tr\u00ecnh:<\/span><\/p>\n<ul>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">\u1ea8n d\u1eef li\u1ec7u: M\u1ed9t t\u00ednh n\u0103ng c\u1ee7a ng\u00f4n ng\u1eef \u0111\u1ec3 h\u1ea1n ch\u1ebf truy c\u1eadp v\u00e0o c\u00e1c th\u00e0nh ph\u1ea7n c\u1ee7a m\u1ed9t \u0111\u1ed1i t\u01b0\u1ee3ng. V\u00ed d\u1ee5, c\u00e1c th\u00e0nh ph\u1ea7n private v\u00e0 protected trong C++.<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">\u0110\u00f3ng g\u00f3i d\u1eef li\u1ec7u v\u00e0 ph\u01b0\u01a1ng th\u1ee9c: D\u1eef li\u1ec7u v\u00e0 c\u00e1c ph\u01b0\u01a1ng th\u1ee9c ho\u1ea1t \u0111\u1ed9ng tr\u00ean d\u1eef li\u1ec7u \u0111\u00f3 \u0111\u01b0\u1ee3c g\u00f3i g\u1ecdn l\u1ea1i v\u1edbi nhau. V\u00ed d\u1ee5, c\u00e1c th\u00e0nh ph\u1ea7n d\u1eef li\u1ec7u v\u00e0 c\u00e1c ph\u01b0\u01a1ng th\u1ee9c th\u00e0nh ph\u1ea7n ho\u1ea1t \u0111\u1ed9ng tr\u00ean ch\u00fang \u0111\u01b0\u1ee3c \u0111\u00f3ng g\u00f3i th\u00e0nh m\u1ed9t \u0111\u01a1n v\u1ecb duy nh\u1ea5t \u0111\u01b0\u1ee3c g\u1ecdi l\u00e0 class.<\/span><\/li>\n<\/ul>\n<h3><b> Polymorphism (t\u00ednh \u0111a h\u00ecnh) l\u00e0 g\u00ec? C\u00f3 nh\u1eefng lo\u1ea1i Polymorphism n\u00e0o?<\/b><\/h3>\n<p><span style=\"font-weight: 400;\">\u0110a h\u00ecnh l\u00e0 m\u1ed9t trong nh\u1eefng kh\u00e1i ni\u1ec7m c\u1ed1t l\u00f5i v\u00e0 \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng nhi\u1ec1u nh\u1ea5t trong ng\u00f4n ng\u1eef OOP. T\u00ednh \u0111a h\u00ecnh gi\u1ea3i th\u00edch kh\u00e1i ni\u1ec7m c\u00e1c class kh\u00e1c nhau c\u00f3 th\u1ec3 \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng v\u1edbi c\u00f9ng m\u1ed9t giao di\u1ec7n. M\u1ed7i class n\u00e0y c\u0169ng c\u00f3 th\u1ec3 c\u00f3 tri\u1ec3n khai giao di\u1ec7n ri\u00eang. \u0110a h\u00ecnh \u0111\u01b0\u1ee3c ph\u00e2n lo\u1ea1i th\u00e0nh hai lo\u1ea1i d\u1ef1a tr\u00ean th\u1eddi gian khi l\u1ec7nh g\u1ecdi \u0111\u1ebfn \u0111\u1ed1i t\u01b0\u1ee3ng ho\u1eb7c h\u00e0m \u0111\u01b0\u1ee3c gi\u1ea3i quy\u1ebft:<\/span><\/p>\n<ul>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">Compile-Time Polymorphism (\u0111a h\u00ecnh th\u1eddi gian bi\u00ean d\u1ecbch): \u0110a h\u00ecnh th\u1eddi gian bi\u00ean d\u1ecbch, c\u00f2n \u0111\u01b0\u1ee3c g\u1ecdi l\u00e0 static polymorphism ho\u1eb7c early binding l\u00e0 lo\u1ea1i \u0111a h\u00ecnh trong \u0111\u00f3 li\u00ean k\u1ebft l\u1ec7nh \u0111\u1ebfn m\u00e3 c\u1ee7a n\u00f3 \u0111\u01b0\u1ee3c th\u1ef1c hi\u1ec7n t\u1ea1i th\u1eddi \u0111i\u1ec3m bi\u00ean d\u1ecbch. Method overloading v\u00e0 operator overloading l\u00e0 v\u00ed d\u1ee5 v\u1ec1 \u0111a h\u00ecnh th\u1eddi gian bi\u00ean d\u1ecbch.<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">Runtime Polymorphism (\u0111a h\u00ecnh th\u1eddi gian ch\u1ea1y): C\u00f2n \u0111\u01b0\u1ee3c g\u1ecdi l\u00e0 dynamic polymorphism ho\u1eb7c late binding, l\u00e0 lo\u1ea1i \u0111a h\u00ecnh trong \u0111\u00f3 vi\u1ec7c tri\u1ec3n khai th\u1ef1c t\u1ebf c\u1ee7a h\u00e0m \u0111\u01b0\u1ee3c x\u00e1c \u0111\u1ecbnh trong th\u1eddi gian ch\u1ea1y ho\u1eb7c th\u1ef1c thi. Method overriding l\u00e0 m\u1ed9t v\u00ed d\u1ee5 v\u1ec1 ph\u01b0\u01a1ng th\u1ee9c n\u00e0y.<\/span><\/li>\n<\/ul>\n<h3><b> Abstraction (t\u00ednh tr\u1eebu t\u01b0\u1ee3ng) l\u00e0 g\u00ec? Vi\u1ec7c tr\u1eebu t\u01b0\u1ee3ng h\u00f3a d\u1eef li\u1ec7u \u0111\u01b0\u1ee3c th\u1ef1c hi\u1ec7n nh\u01b0 th\u1ebf n\u00e0o?<\/b><\/h3>\n<p><span style=\"font-weight: 400;\">N\u1ebfu b\u1ea1n l\u00e0 ng\u01b0\u1eddi d\u00f9ng v\u00e0 b\u1ea1n c\u00f3 m\u1ed9t problem statement, b\u1ea1n kh\u00f4ng mu\u1ed1n bi\u1ebft c\u00e1c th\u00e0nh ph\u1ea7n c\u1ee7a ph\u1ea7n m\u1ec1m ho\u1ea1t \u0111\u1ed9ng nh\u01b0 th\u1ebf n\u00e0o ho\u1eb7c n\u00f3 \u0111\u01b0\u1ee3c t\u1ea1o ra nh\u01b0 th\u1ebf n\u00e0o. B\u1ea1n ch\u1ec9 mu\u1ed1n bi\u1ebft ph\u1ea7n m\u1ec1m gi\u1ea3i quy\u1ebft v\u1ea5n \u0111\u1ec1 c\u1ee7a b\u1ea1n nh\u01b0 th\u1ebf n\u00e0o. L\u00fac n\u00e0y, tr\u1eebu t\u01b0\u1ee3ng h\u00f3a l\u00e0 ph\u01b0\u01a1ng ph\u00e1p \u1ea9n c\u00e1c chi ti\u1ebft kh\u00f4ng c\u1ea7n thi\u1ebft kh\u1ecfi c\u00e1c chi ti\u1ebft c\u1ea7n thi\u1ebft.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">\u0110\u00e2y l\u00e0 m\u1ed9t trong nh\u1eefng t\u00ednh n\u0103ng ch\u00ednh c\u1ee7a OOP. Tr\u1eebu t\u01b0\u1ee3ng h\u00f3a \u0111\u01b0\u1ee3c tri\u1ec3n khai b\u1eb1ng c\u00e1ch s\u1eed d\u1ee5ng c\u00e1c class v\u00e0 giao di\u1ec7n.<\/span><\/p>\n<h3><b> Ngo\u00e0i OOP, c\u00f2n c\u00f3 nh\u1eefng m\u00f4 h\u00ecnh l\u1eadp tr\u00ecnh n\u00e0o kh\u00e1c?<\/b><\/h3>\n<p><span style=\"font-weight: 400;\">C\u00e1c m\u00f4 h\u00ecnh l\u1eadp tr\u00ecnh \u0111\u1ec1 c\u1eadp \u0111\u1ebfn ph\u01b0\u01a1ng ph\u00e1p ph\u00e2n lo\u1ea1i ng\u00f4n ng\u1eef l\u1eadp tr\u00ecnh d\u1ef1a tr\u00ean c\u00e1c t\u00ednh n\u0103ng c\u1ee7a ch\u00fang. V\u1ec1 c\u01a1 b\u1ea3n c\u00f3 hai lo\u1ea1i m\u00f4 h\u00ecnh l\u1eadp tr\u00ecnh:<\/span><\/p>\n<p><span style=\"font-weight: 400;\"><strong>M\u00f4 h\u00ecnh l\u1eadp tr\u00ecnh m\u1ec7nh l\u1ec7nh:<\/strong> L\u1eadp tr\u00ecnh m\u1ec7nh l\u1ec7nh t\u1eadp trung v\u00e0o c\u00e1ch th\u1ef1c thi logic ch\u01b0\u01a1ng tr\u00ecnh v\u00e0 \u0111\u1ecbnh ngh\u0129a control flow l\u00e0 c\u00e1c c\u00e2u l\u1ec7nh thay \u0111\u1ed5i tr\u1ea1ng th\u00e1i ch\u01b0\u01a1ng tr\u00ecnh. C\u00f3 th\u1ec3 \u0111\u01b0\u1ee3c ph\u00e2n lo\u1ea1i th\u00eam th\u00e0nh:<\/span><\/p>\n<ul>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">M\u00f4 h\u00ecnh l\u1eadp tr\u00ecnh th\u1ee7 t\u1ee5c: L\u1eadp tr\u00ecnh th\u1ee7 t\u1ee5c ch\u1ec9 \u0111\u1ecbnh c\u00e1c b\u01b0\u1edbc m\u00e0 ch\u01b0\u01a1ng tr\u00ecnh ph\u1ea3i th\u1ef1c hi\u1ec7n \u0111\u1ec3 \u0111\u1ea1t \u0111\u1ebfn tr\u1ea1ng th\u00e1i mong mu\u1ed1n, th\u01b0\u1eddng \u0111\u01b0\u1ee3c \u0111\u1ecdc theo th\u1ee9 t\u1ef1 t\u1eeb tr\u00ean xu\u1ed1ng d\u01b0\u1edbi.<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">L\u1eadp tr\u00ecnh h\u01b0\u1edbng \u0111\u1ed1i t\u01b0\u1ee3ng ho\u1eb7c OOP: OOP t\u1ed5 ch\u1ee9c c\u00e1c ch\u01b0\u01a1ng tr\u00ecnh d\u01b0\u1edbi d\u1ea1ng c\u00e1c object, ch\u1ee9a m\u1ed9t s\u1ed1 d\u1eef li\u1ec7u v\u00e0 h\u00e0nh vi.<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">L\u1eadp tr\u00ecnh song song: M\u00f4 h\u00ecnh l\u1eadp tr\u00ecnh song song chia m\u1ed9t t\u00e1c v\u1ee5 th\u00e0nh c\u00e1c t\u00e1c v\u1ee5 con v\u00e0 t\u1eadp trung v\u00e0o vi\u1ec7c th\u1ef1c hi\u1ec7n ch\u00fang \u0111\u1ed3ng th\u1eddi t\u1ea1i c\u00f9ng m\u1ed9t th\u1eddi \u0111i\u1ec3m.<\/span><\/li>\n<\/ul>\n<p><span style=\"font-weight: 400;\"><strong>M\u00f4 h\u00ecnh l\u1eadp tr\u00ecnh khai b\u00e1o:<\/strong> L\u1eadp tr\u00ecnh khai b\u00e1o t\u1eadp trung v\u00e0o nh\u1eefng g\u00ec c\u1ea7n th\u1ef1c thi v\u00e0 \u0111\u1ecbnh ngh\u0129a logic ch\u01b0\u01a1ng tr\u00ecnh, nh\u01b0ng kh\u00f4ng ph\u1ea3i l\u00e0 control flow chi ti\u1ebft. M\u00f4 h\u00ecnh khai b\u00e1o c\u00f3 th\u1ec3 \u0111\u01b0\u1ee3c ph\u00e2n lo\u1ea1i th\u00e0nh:<\/span><\/p>\n<ul>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">M\u00f4 h\u00ecnh l\u1eadp tr\u00ecnh logic: M\u00f4 h\u00ecnh l\u1eadp tr\u00ecnh logic d\u1ef1a tr\u00ean logic h\u00ecnh th\u1ee9c, \u0111\u1ec1 c\u1eadp \u0111\u1ebfn m\u1ed9t t\u1eadp h\u1ee3p c\u00e1c c\u00e2u th\u1ec3 hi\u1ec7n s\u1ef1 ki\u1ec7n v\u00e0 quy t\u1eafc gi\u1ea3i quy\u1ebft m\u1ed9t v\u1ea5n \u0111\u1ec1<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">M\u00f4 h\u00ecnh l\u1eadp tr\u00ecnh h\u00e0m: L\u1eadp tr\u00ecnh h\u00e0m (Functional Programming) l\u00e0 m\u1ed9t m\u00f4 h\u00ecnh l\u1eadp tr\u00ecnh trong \u0111\u00f3 c\u00e1c ch\u01b0\u01a1ng tr\u00ecnh \u0111\u01b0\u1ee3c x\u00e2y d\u1ef1ng b\u1eb1ng c\u00e1ch \u00e1p d\u1ee5ng v\u00e0 bi\u00ean so\u1ea1n c\u00e1c h\u00e0m.<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">M\u00f4 h\u00ecnh l\u1eadp tr\u00ecnh c\u01a1 s\u1edf d\u1eef li\u1ec7u: \u0110\u01b0\u1ee3c s\u1eed d\u1ee5ng \u0111\u1ec3 qu\u1ea3n l\u00fd d\u1eef li\u1ec7u v\u00e0 th\u00f4ng tin \u0111\u01b0\u1ee3c c\u1ea5u tr\u00fac d\u01b0\u1edbi d\u1ea1ng tr\u01b0\u1eddng, b\u1ea3n ghi v\u00e0 t\u1ec7p.<\/span><\/li>\n<\/ul>\n<h2><span class=\"ez-toc-section\" id=\"Cac_cau_hoi_phong_van_OOP_cap_do_Junior_Developer\"><\/span><strong>C\u00e1c c\u00e2u h\u1ecfi ph\u1ecfng v\u1ea5n OOP c\u1ea5p \u0111\u1ed9 Junior Developer<\/strong><span class=\"ez-toc-section-end\"><\/span><\/h2>\n<h3><b> S\u1ef1 kh\u00e1c bi\u1ec7t gi\u1eefa l\u1eadp tr\u00ecnh th\u1ee7 t\u1ee5c (SOP) v\u00e0 l\u1eadp tr\u00ecnh h\u01b0\u1edbng \u0111\u1ed1i t\u01b0\u1ee3ng (OOP)?<\/b><\/h3>\n<p><span style=\"font-weight: 400;\">S\u1ef1 kh\u00e1c bi\u1ec7t quan tr\u1ecdng gi\u1eefa L\u1eadp tr\u00ecnh h\u01b0\u1edbng \u0111\u1ed1i t\u01b0\u1ee3ng (OOP) v\u00e0 L\u1eadp tr\u00ecnh th\u1ee7 t\u1ee5c (c\u00f2n g\u1ecdi l\u00e0 L\u1eadp tr\u00ecnh c\u00f3 c\u1ea5u tr\u00fac &#8211; Structured Programming) n\u1eb1m \u1edf c\u00e1ch ti\u1ebfp c\u1eadn c\u1ee7a ch\u00fang \u0111\u1ed1i v\u1edbi vi\u1ec7c t\u1ed5 ch\u1ee9c v\u00e0 thi\u1ebft k\u1ebf ch\u01b0\u01a1ng tr\u00ecnh:<\/span><\/p>\n<table>\n<tbody>\n<tr>\n<td><b>L\u1eadp tr\u00ecnh h\u01b0\u1edbng \u0111\u1ed1i t\u01b0\u1ee3ng (OOP)<\/b><\/td>\n<td><b>L\u1eadp tr\u00ecnh th\u1ee7 t\u1ee5c (Structured Programming)<\/b><\/td>\n<\/tr>\n<tr>\n<td><span style=\"font-weight: 400;\">L\u1eadp tr\u00ecnh h\u01b0\u1edbng \u0111\u1ed1i t\u01b0\u1ee3ng \u0111\u01b0\u1ee3c x\u00e2y d\u1ef1ng tr\u00ean c\u00e1c \u0111\u1ed1i t\u01b0\u1ee3ng c\u00f3 tr\u1ea1ng th\u00e1i v\u00e0 h\u00e0nh vi.<\/span><\/td>\n<td><span style=\"font-weight: 400;\">C\u1ea5u tr\u00fac logic c\u1ee7a ch\u01b0\u01a1ng tr\u00ecnh \u0111\u01b0\u1ee3c cung c\u1ea5p b\u1edfi l\u1eadp tr\u00ecnh c\u1ea5u tr\u00fac, chia ch\u01b0\u01a1ng tr\u00ecnh th\u00e0nh c\u00e1c ch\u1ee9c n\u0103ng t\u01b0\u01a1ng \u1ee9ng.<\/span><\/td>\n<\/tr>\n<tr>\n<td><span style=\"font-weight: 400;\">Ch\u01b0\u01a1ng tr\u00ecnh \u0111\u01b0\u1ee3c t\u1ed5 ch\u1ee9c th\u00e0nh c\u00e1c l\u1edbp, trong \u0111\u00f3 m\u1ed7i l\u1edbp ch\u1ee9a d\u1eef li\u1ec7u (thu\u1ed9c t\u00ednh) v\u00e0 c\u00e1c ph\u01b0\u01a1ng th\u1ee9c (h\u00e0nh vi) \u0111\u1ec3 thao t\u00e1c tr\u00ean d\u1eef li\u1ec7u \u0111\u00f3 v\u00e0 c\u00f3 th\u1ec3 t\u01b0\u01a1ng t\u00e1c v\u1edbi nhau th\u00f4ng qua c\u00e1c ph\u01b0\u01a1ng th\u1ee9c.<\/span><\/td>\n<td><span style=\"font-weight: 400;\">Ch\u01b0\u01a1ng tr\u00ecnh \u0111\u01b0\u1ee3c chia th\u00e0nh c\u00e1c h\u00e0m v\u00e0 th\u1ee7 t\u1ee5c. D\u1eef li\u1ec7u v\u00e0 h\u00e0m th\u01b0\u1eddng \u0111\u01b0\u1ee3c t\u1ed5 ch\u1ee9c ri\u00eang r\u1ebd. D\u1eef li\u1ec7u \u0111\u01b0\u1ee3c truy\u1ec1n v\u00e0o h\u00e0m th\u00f4ng qua c\u00e1c tham s\u1ed1, v\u00e0 c\u00e1c h\u00e0m c\u00f3 th\u1ec3 s\u1eeda \u0111\u1ed5i d\u1eef li\u1ec7u to\u00e0n c\u1ee5c.<\/span><\/td>\n<\/tr>\n<tr>\n<td><span style=\"font-weight: 400;\">H\u1ea1n ch\u1ebf lu\u1ed3ng d\u1eef li\u1ec7u m\u1edf ch\u1ec9 d\u00e0nh cho nh\u1eefng b\u1ed9 ph\u1eadn \u0111\u01b0\u1ee3c \u1ee7y quy\u1ec1n, qua \u0111\u00f3 cung c\u1ea5p kh\u1ea3 n\u0103ng b\u1ea3o m\u1eadt d\u1eef li\u1ec7u t\u1ed1t h\u01a1n.<\/span><\/td>\n<td><span style=\"font-weight: 400;\">Kh\u00f4ng h\u1ea1n ch\u1ebf lu\u1ed3ng d\u1eef li\u1ec7u. B\u1ea5t k\u1ef3 ai c\u0169ng c\u00f3 th\u1ec3 truy c\u1eadp d\u1eef li\u1ec7u.<\/span><\/td>\n<\/tr>\n<tr>\n<td><span style=\"font-weight: 400;\">Kh\u1ea3 n\u0103ng t\u00e1i s\u1eed d\u1ee5ng m\u00e3 \u0111\u01b0\u1ee3c c\u1ea3i thi\u1ec7n nh\u1edd v\u00e0o c\u00e1c kh\u00e1i ni\u1ec7m \u0111a h\u00ecnh v\u00e0 k\u1ebf th\u1eeba.<\/span><\/td>\n<td><span style=\"font-weight: 400;\">Kh\u1ea3 n\u0103ng t\u00e1i s\u1eed d\u1ee5ng m\u00e3 \u0111\u1ea1t \u0111\u01b0\u1ee3c b\u1eb1ng c\u00e1ch s\u1eed d\u1ee5ng c\u00e1c h\u00e0m v\u00e0 v\u00f2ng l\u1eb7p.<\/span><\/td>\n<\/tr>\n<tr>\n<td><span style=\"font-weight: 400;\">C\u00e1c ph\u01b0\u01a1ng th\u1ee9c ho\u1ea1t \u0111\u1ed9ng theo ki\u1ec3u \u0111\u1ed9ng, th\u1ef1c hi\u1ec7n c\u00e1c l\u1ec7nh g\u1ecdi d\u1ef1a tr\u00ean h\u00e0nh vi c\u1ee7a \u0111\u1ed1i t\u01b0\u1ee3ng v\u00e0 nhu c\u1ea7u c\u1ee7a m\u00e3 khi ch\u1ea1y.<\/span><\/td>\n<td><span style=\"font-weight: 400;\">C\u00e1c h\u00e0m \u0111\u01b0\u1ee3c g\u1ecdi tu\u1ea7n t\u1ef1 v\u00e0 c\u00e1c d\u00f2ng m\u00e3 \u0111\u01b0\u1ee3c x\u1eed l\u00fd t\u1eebng b\u01b0\u1edbc.<\/span><\/td>\n<\/tr>\n<tr>\n<td><span style=\"font-weight: 400;\">Vi\u1ec7c s\u1eeda \u0111\u1ed5i v\u00e0 c\u1eadp nh\u1eadt m\u00e3 d\u1ec5 d\u00e0ng h\u01a1n.<\/span><\/td>\n<td><span style=\"font-weight: 400;\">Vi\u1ec7c s\u1eeda \u0111\u1ed5i m\u00e3 kh\u00f3 h\u01a1n so v\u1edbi OOP.<\/span><\/td>\n<\/tr>\n<tr>\n<td><span style=\"font-weight: 400;\">D\u1eef li\u1ec7u \u0111\u01b0\u1ee3c coi tr\u1ecdng h\u01a1n trong OOP.<\/span><\/td>\n<td><span style=\"font-weight: 400;\">M\u00e3 \u0111\u01b0\u1ee3c coi tr\u1ecdng h\u01a1n.<\/span><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<h3><b> L\u1eadp tr\u00ecnh c\u00f3 c\u1ea5u tr\u00fac l\u00e0 g\u00ec?<\/b><\/h3>\n<p><span style=\"font-weight: 400;\">L\u1eadp tr\u00ecnh c\u00f3 c\u1ea5u tr\u00fac \u0111\u1ec1 c\u1eadp \u0111\u1ebfn ph\u01b0\u01a1ng ph\u00e1p l\u1eadp tr\u00ecnh bao g\u1ed3m control flow c\u00f3 c\u1ea5u tr\u00fac ho\u00e0n ch\u1ec9nh. \u1ede \u0111\u00e2y, c\u1ea5u tr\u00fac \u0111\u1ec1 c\u1eadp \u0111\u1ebfn m\u1ed9t kh\u1ed1i, ch\u1ee9a m\u1ed9t t\u1eadp h\u1ee3p c\u00e1c quy t\u1eafc v\u00e0 c\u00f3 control flow x\u00e1c \u0111\u1ecbnh, ch\u1eb3ng h\u1ea1n nh\u01b0 (if\/then\/else), (while\/for), c\u1ea5u tr\u00fac kh\u1ed1i v\u00e0 ch\u01b0\u01a1ng tr\u00ecnh con. H\u1ea7u nh\u01b0 t\u1ea5t c\u1ea3 c\u00e1c m\u00f4 h\u00ecnh l\u1eadp tr\u00ecnh \u0111\u1ec1u bao g\u1ed3m l\u1eadp tr\u00ecnh c\u00f3 c\u1ea5u tr\u00fac, bao g\u1ed3m c\u1ea3 m\u00f4 h\u00ecnh OOP.<\/span><\/p>\n<h3><b> Tr\u1eebu t\u01b0\u1ee3ng h\u00f3a d\u1eef li\u1ec7u l\u00e0 g\u00ec?<\/b><\/h3>\n<p><span style=\"font-weight: 400;\">Tr\u1eebu t\u01b0\u1ee3ng h\u00f3a d\u1eef li\u1ec7u th\u1ef1c s\u1ef1 l\u00e0 m\u1ed9t t\u00ednh n\u0103ng quan tr\u1ecdng c\u1ee7a l\u1eadp tr\u00ecnh h\u01b0\u1edbng \u0111\u1ed1i t\u01b0\u1ee3ng. N\u00f3 bao g\u1ed3m vi\u1ec7c ch\u1ec9 hi\u1ec3n th\u1ecb th\u00f4ng tin c\u1ea7n thi\u1ebft trong khi \u1ea9n c\u00e1c chi ti\u1ebft tri\u1ec3n khai. V\u00ed d\u1ee5, khi s\u1eed d\u1ee5ng \u0111i\u1ec7n tho\u1ea1i di \u0111\u1ed9ng, b\u1ea1n bi\u1ebft c\u00e1ch nh\u1eafn tin ho\u1eb7c g\u1ecdi \u0111i\u1ec7n cho ai \u0111\u00f3, nh\u01b0ng b\u1ea1n kh\u00f4ng c\u1ea7n bi\u1ebft c\u00e1c quy tr\u00ecnh k\u1ef9 thu\u1eadt ph\u1ee9c t\u1ea1p \u0111\u1eb1ng sau n\u00f3.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">\u0110i\u1ec1u n\u00e0y minh h\u1ecda cho vi\u1ec7c tr\u1eebu t\u01b0\u1ee3ng h\u00f3a d\u1eef li\u1ec7u v\u00ec n\u00f3 b\u1ea3o v\u1ec7 ng\u01b0\u1eddi d\u00f9ng kh\u1ecfi nh\u1eefng ph\u1ee9c t\u1ea1p kh\u00f4ng c\u1ea7n thi\u1ebft, t\u1eadp trung v\u00e0o c\u00e1c h\u00e0nh \u0111\u1ed9ng h\u1ecd c\u00f3 th\u1ec3 th\u1ef1c hi\u1ec7n m\u00e0 kh\u00f4ng g\u00e2y th\u00eam g\u00e1nh n\u1eb7ng v\u1ec1 c\u00e1c chi ti\u1ebft tri\u1ec3n khai. C\u00f3 th\u1ec3 th\u1ef1c hi\u1ec7n tr\u1eebu t\u01b0\u1ee3ng h\u00f3a d\u1eef li\u1ec7u b\u1eb1ng hai c\u00e1ch:<\/span><\/p>\n<ul>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">Abstraction class (l\u1edbp tr\u1eebu t\u01b0\u1ee3ng)<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">Abstraction method (ph\u01b0\u01a1ng th\u1ee9c tr\u1eebu t\u01b0\u1ee3ng)<\/span><\/li>\n<\/ul>\n<h3><b> Ph\u00e2n bi\u1ec7t gi\u1eefa tr\u1eebu t\u01b0\u1ee3ng h\u00f3a d\u1eef li\u1ec7u v\u00e0 \u0111\u00f3ng g\u00f3i d\u1eef li\u1ec7u<\/b><\/h3>\n<table>\n<tbody>\n<tr>\n<td><b>Tr\u1eebu t\u01b0\u1ee3ng h\u00f3a d\u1eef li\u1ec7u (data abstraction)<\/b><\/td>\n<td><b>\u0110\u00f3ng g\u00f3i d\u1eef li\u1ec7u (encapsulation)<\/b><\/td>\n<\/tr>\n<tr>\n<td><span style=\"font-weight: 400;\">Gi\u1ea3i quy\u1ebft v\u1ea5n \u0111\u1ec1 \u1edf c\u1ea5p \u0111\u1ed9 thi\u1ebft k\u1ebf<\/span><\/td>\n<td><span style=\"font-weight: 400;\">Gi\u1ea3i quy\u1ebft v\u1ea5n \u0111\u1ec1 \u1edf c\u1ea5p \u0111\u1ed9 tri\u1ec3n khai<\/span><\/td>\n<\/tr>\n<tr>\n<td><span style=\"font-weight: 400;\">Gi\u00fap \u1ea9n c\u00e1c chi ti\u1ebft th\u1ef1c hi\u1ec7n<\/span><\/td>\n<td><span style=\"font-weight: 400;\">Gom m\u00e3 v\u00e0 d\u1eef li\u1ec7u l\u1ea1i v\u1edbi nhau th\u00e0nh m\u1ed9t \u0111\u01a1n v\u1ecb duy nh\u1ea5t v\u00e0 gi\u00fap \u1ea9n \u0111i<\/span><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<h3><b>Virtual functions l\u00e0 g\u00ec?<\/b><\/h3>\n<p><span style=\"font-weight: 400;\">Virtual function (h\u00e0m \u1ea3o) \u0111\u01b0\u1ee3c khai b\u00e1o trong m\u1ed9t base class m\u00e0 c\u00e1c derived class c\u00f3 th\u1ec3 overriding. Ch\u00fang cho ph\u00e9p \u0111a h\u00ecnh \u0111\u1ed9ng, cho ph\u00e9p l\u1ef1a ch\u1ecdn tri\u1ec3n khai h\u00e0m th\u00edch h\u1ee3p t\u1ea1i runtime d\u1ef1a tr\u00ean lo\u1ea1i \u0111\u1ed1i t\u01b0\u1ee3ng. Trong c\u00e1c ng\u00f4n ng\u1eef nh\u01b0 C++, c\u00e1c h\u00e0m \u1ea3o \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng \u0111\u1ec3 \u0111\u1ea1t \u0111\u01b0\u1ee3c late binding ho\u1eb7c \u0111a h\u00ecnh runtime.<\/span><\/p>\n<h3><b> Constructor l\u00e0 g\u00ec? C\u00e1c lo\u1ea1i constructor<\/b><\/h3>\n<p><span style=\"font-weight: 400;\">M\u1ed9t Constructor l\u00e0 m\u1ed9t block code kh\u1edfi t\u1ea1o \u0111\u1ed1i t\u01b0\u1ee3ng m\u1edbi. Constructor l\u00e0 c\u00e1c ph\u01b0\u01a1ng th\u1ee9c duy nh\u1ea5t trong m\u1ed9t class \u0111\u01b0\u1ee3c t\u1ef1 \u0111\u1ed9ng g\u1ecdi khi m\u1ed9t instance c\u1ee7a class \u0111\u01b0\u1ee3c t\u1ea1o. Ch\u00fang \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng \u0111\u1ec3 kh\u1edfi t\u1ea1o tr\u1ea1ng th\u00e1i c\u1ee7a \u0111\u1ed1i t\u01b0\u1ee3ng ho\u1eb7c th\u1ef1c hi\u1ec7n b\u1ea5t k\u1ef3 ho\u1ea1t \u0111\u1ed9ng thi\u1ebft l\u1eadp c\u1ea7n thi\u1ebft n\u00e0o. Constructor th\u01b0\u1eddng l\u00e0 ph\u01b0\u01a1ng th\u1ee9c c\u00f3 c\u00f9ng t\u00ean v\u1edbi class nh\u01b0ng c\u0169ng c\u00f3 th\u1ec3 kh\u00e1c trong m\u1ed9t s\u1ed1 ng\u00f4n ng\u1eef. V\u00ed d\u1ee5:<\/span><\/p>\n<ul>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">Trong Python, h\u00e0m t\u1ea1o \u0111\u01b0\u1ee3c \u0111\u1eb7t t\u00ean l\u00e0<\/span><span style=\"font-weight: 400;\"> __init__<\/span><span style=\"font-weight: 400;\">.\u00a0<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">Trong C++ v\u00e0 Java, h\u00e0m t\u1ea1o \u0111\u01b0\u1ee3c \u0111\u1eb7t t\u00ean gi\u1ed1ng nh\u01b0 t\u00ean class.<\/span><\/li>\n<\/ul>\n<p><span style=\"font-weight: 400;\">V\u00ed d\u1ee5:<\/span><\/p>\n<p><span style=\"font-weight: 400;\">Trong C++:<\/span><\/p>\n<pre><span style=\"font-weight: 400;\">class<\/span> <span style=\"font-weight: 400;\">base<\/span><span style=\"font-weight: 400;\"> {<\/span>\r\n<span style=\"font-weight: 400;\">\u00a0 \u00a0 <\/span><span style=\"font-weight: 400;\">public<\/span><span style=\"font-weight: 400;\">:<\/span>\r\n<span style=\"font-weight: 400;\">\u00a0 \u00a0 \u00a0 \u00a0 <\/span><span style=\"font-weight: 400;\">base<\/span><span style=\"font-weight: 400;\">() { cout &lt;&lt; <\/span><span style=\"font-weight: 400;\">\"\u0110\u00e2y l\u00e0 constructor\"<\/span><span style=\"font-weight: 400;\">; }<\/span>\r\n<span style=\"font-weight: 400;\">}<\/span><\/pre>\n<p><span style=\"font-weight: 400;\">Trong Java:<\/span><\/p>\n<pre><span style=\"font-weight: 400;\">class<\/span> <span style=\"font-weight: 400;\">base<\/span><span style=\"font-weight: 400;\"> {<\/span>\r\n<span style=\"font-weight: 400;\">\u00a0 \u00a0 <\/span><span style=\"font-weight: 400;\">base<\/span><span style=\"font-weight: 400;\">() { System.<\/span><span style=\"font-weight: 400;\">out<\/span><span style=\"font-weight: 400;\">.printIn(<\/span><span style=\"font-weight: 400;\">\"\u0110\u00e2y l\u00e0 constructor\"<\/span><span style=\"font-weight: 400;\">); }<\/span>\r\n<span style=\"font-weight: 400;\">}<\/span><\/pre>\n<p><span style=\"font-weight: 400;\">Trong Python:<\/span><\/p>\n<pre><span style=\"font-weight: 400;\">class<\/span> <span style=\"font-weight: 400;\">base<\/span><span style=\"font-weight: 400;\">:<\/span>\r\n<span style=\"font-weight: 400;\">\u00a0 \u00a0 <\/span><span style=\"font-weight: 400;\">def<\/span> <span style=\"font-weight: 400;\">__init__<\/span><span style=\"font-weight: 400;\">(<\/span><span style=\"font-weight: 400;\">self<\/span><span style=\"font-weight: 400;\">):<\/span>\r\n<span style=\"font-weight: 400;\">\u00a0 \u00a0 \u00a0 \u00a0 print(<\/span><span style=\"font-weight: 400;\">\"\u0110\u00e2y l\u00e0 constructor\"<\/span><span style=\"font-weight: 400;\">)<\/span><\/pre>\n<p><span style=\"font-weight: 400;\">C\u00f3 c\u00e1c lo\u1ea1i Constructor sau:<\/span><\/p>\n<ul>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">Private Constructor (h\u00e0m ri\u00eang t\u01b0): \u0110i\u1ec1u n\u00e0y h\u1ea1n ch\u1ebf vi\u1ec7c kh\u1edfi t\u1ea1o m\u1ed9t class t\u1eeb b\u00ean ngo\u00e0i. N\u00f3 th\u01b0\u1eddng \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng cho c\u00e1c class ti\u1ec7n \u00edch c\u00f3 ph\u01b0\u01a1ng th\u1ee9c t\u0129nh.<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">Default Constructor (h\u00e0m m\u1eb7c \u0111\u1ecbnh): N\u1ebfu kh\u00f4ng c\u00f3 h\u00e0m t\u1ea1o n\u00e0o \u0111\u01b0\u1ee3c \u0111\u1ecbnh ngh\u0129a r\u00f5 r\u00e0ng, n\u00f3 s\u1ebd \u0111\u01b0\u1ee3c tr\u00ecnh bi\u00ean d\u1ecbch t\u1ef1 \u0111\u1ed9ng t\u1ea1o ra v\u00e0 kh\u1edfi t\u1ea1o c\u00e1c bi\u1ebfn th\u1ec3 hi\u1ec7n th\u00e0nh gi\u00e1 tr\u1ecb m\u1eb7c \u0111\u1ecbnh.<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">Copy Constructor (h\u00e0m sao ch\u00e9p): H\u00e0m n\u00e0y t\u1ea1o ra m\u1ed9t \u0111\u1ed1i t\u01b0\u1ee3ng m\u1edbi b\u1eb1ng c\u00e1ch sao ch\u00e9p tr\u1ea1ng th\u00e1i c\u1ee7a m\u1ed9t \u0111\u1ed1i t\u01b0\u1ee3ng hi\u1ec7n c\u00f3. N\u00f3 \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng \u0111\u1ec3 t\u1ea1o b\u1ea3n sao.<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">Static Constructor (h\u00e0m t\u0129nh): Kh\u1edfi t\u1ea1o c\u00e1c th\u00e0nh ph\u1ea7n d\u1eef li\u1ec7u t\u0129nh ho\u1eb7c th\u1ef1c hi\u1ec7n c\u00e1c t\u00e1c v\u1ee5 thi\u1ebft l\u1eadp m\u1ed9t l\u1ea7n cho class, ch\u1ec9 \u0111\u01b0\u1ee3c th\u1ef1c thi m\u1ed9t l\u1ea7n khi class \u0111\u01b0\u1ee3c t\u1ea3i.<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">Parameterized Constructor (h\u00e0m tham s\u1ed1): Ch\u1ea5p nh\u1eadn tham s\u1ed1 \u0111\u1ec3 kh\u1edfi t\u1ea1o c\u00e1c bi\u1ebfn th\u00e0nh ph\u1ea7n trong qu\u00e1 tr\u00ecnh t\u1ea1o \u0111\u1ed1i t\u01b0\u1ee3ng, cho ph\u00e9p t\u00f9y ch\u1ec9nh tr\u1ea1ng th\u00e1i c\u1ee7a \u0111\u1ed1i t\u01b0\u1ee3ng.<\/span><\/li>\n<\/ul>\n<h3><b> Tr\u00ecnh Copy constructor l\u00e0 g\u00ec?<\/b><\/h3>\n<p><span style=\"font-weight: 400;\">Copy Constructor l\u00e0 m\u1ed9t lo\u1ea1i Constructor, c\u00f3 m\u1ee5c \u0111\u00edch sao ch\u00e9p m\u1ed9t \u0111\u1ed1i t\u01b0\u1ee3ng sang m\u1ed9t \u0111\u1ed1i t\u01b0\u1ee3ng kh\u00e1c. \u0110i\u1ec1u \u0111\u00f3 c\u00f3 ngh\u0129a l\u00e0 m\u1ed9t Copy constructor s\u1ebd sao ch\u00e9p m\u1ed9t \u0111\u1ed1i t\u01b0\u1ee3ng v\u00e0 c\u00e1c gi\u00e1 tr\u1ecb c\u1ee7a n\u00f3 v\u00e0o m\u1ed9t \u0111\u1ed1i t\u01b0\u1ee3ng kh\u00e1c, v\u1edbi \u0111i\u1ec1u ki\u1ec7n l\u00e0 c\u1ea3 hai \u0111\u1ed1i t\u01b0\u1ee3ng \u0111\u1ec1u thu\u1ed9c c\u00f9ng m\u1ed9t class.<\/span><\/p>\n<h3><b> Destructor l\u00e0 g\u00ec?<\/b><\/h3>\n<p><span style=\"font-weight: 400;\">Ng\u01b0\u1ee3c l\u1ea1i v\u1edbi Constructor, kh\u1edfi t\u1ea1o \u0111\u1ed1i t\u01b0\u1ee3ng v\u00e0 ch\u1ec9 \u0111\u1ecbnh kh\u00f4ng gian cho ch\u00fang, Destructor (h\u00e0m h\u1ee7y) c\u0169ng l\u00e0 ph\u01b0\u01a1ng th\u1ee9c \u0111\u1eb7c bi\u1ec7t. Nh\u01b0ng Destructor gi\u1ea3i ph\u00f3ng t\u00e0i nguy\u00ean v\u00e0 b\u1ed9 nh\u1edb m\u00e0 \u0111\u1ed1i t\u01b0\u1ee3ng chi\u1ebfm gi\u1eef. Destructor l\u00e0 ph\u01b0\u01a1ng th\u1ee9c \u0111\u01b0\u1ee3c g\u1ecdi t\u1ef1 \u0111\u1ed9ng khi \u0111\u1ed1i t\u01b0\u1ee3ng h\u1ebft ph\u1ea1m vi ho\u1eb7c b\u1ecb h\u1ee7y. Trong C++, t\u00ean Destructor c\u0169ng gi\u1ed1ng nh\u01b0 t\u00ean class\u00a0 nh\u01b0ng c\u00f3 k\u00fd hi\u1ec7u d\u1ea5u ng\u00e3 ( ~ ) l\u00e0m ti\u1ec1n t\u1ed1. Trong Python, Destructor \u0111\u01b0\u1ee3c \u0111\u1eb7t t\u00ean l\u00e0 __del__ .\u00a0<\/span><\/p>\n<p><span style=\"font-weight: 400;\">V\u00ed d\u1ee5:<\/span><\/p>\n<p><span style=\"font-weight: 400;\">Trong C++:<\/span><\/p>\n<pre><span style=\"font-weight: 400;\">class<\/span> <span style=\"font-weight: 400;\">base<\/span><span style=\"font-weight: 400;\"> {<\/span>\r\n<span style=\"font-weight: 400;\">public<\/span><span style=\"font-weight: 400;\">:<\/span>\r\n <span style=\"font-weight: 400;\">~<\/span><span style=\"font-weight: 400;\">base<\/span><span style=\"font-weight: 400;\">() { cout &lt;&lt; <\/span><span style=\"font-weight: 400;\">\"\u0110\u00e2y l\u00e0 destructor\"<\/span><span style=\"font-weight: 400;\">; }<\/span>\r\n<span style=\"font-weight: 400;\">}<\/span><\/pre>\n<p><span style=\"font-weight: 400;\">Trong Python:<\/span><\/p>\n<pre><span style=\"font-weight: 400;\">class<\/span> <span style=\"font-weight: 400;\">base<\/span><span style=\"font-weight: 400;\">:<\/span>\r\n <span style=\"font-weight: 400;\">def<\/span> <span style=\"font-weight: 400;\">__del__<\/span><span style=\"font-weight: 400;\">(<\/span><span style=\"font-weight: 400;\">self<\/span><span style=\"font-weight: 400;\">):<\/span>\r\n<span style=\"font-weight: 400;\">\u00a0 \u00a0 <\/span> <span style=\"font-weight: 400;\">print(<\/span><span style=\"font-weight: 400;\">\"\u0110\u00e2y l\u00e0 destructor\"<\/span><span style=\"font-weight: 400;\">)<\/span><\/pre>\n<p><span style=\"font-weight: 400;\">Trong Java, tr\u00ecnh thu gom r\u00e1c t\u1ef1 \u0111\u1ed9ng x\u00f3a c\u00e1c \u0111\u1ed1i t\u01b0\u1ee3ng kh\u00f4ng h\u1eefu \u00edch n\u00ean kh\u00f4ng c\u00f3 kh\u00e1i ni\u1ec7m v\u1ec1 Destructor trong Java. Ch\u00fang ta c\u00f3 th\u1ec3 s\u1eed d\u1ee5ng ph\u01b0\u01a1ng th\u1ee9c <\/span><span style=\"font-weight: 400;\">finalize()<\/span><span style=\"font-weight: 400;\"> nh\u01b0 m\u1ed9t gi\u1ea3i ph\u00e1p thay th\u1ebf cho Destructor c\u1ee7a Java nh\u01b0ng n\u00f3 c\u0169ng \u0111\u00e3 l\u1ed7i th\u1eddi k\u1ec3 t\u1eeb Java 9.<\/span><\/p>\n<h3><b> Superclass l\u00e0 g\u00ec?<\/b><\/h3>\n<p><span style=\"font-weight: 400;\">Superclass (hay c\u00f2n g\u1ecdi Base class \/ parent class) c\u0169ng l\u00e0 m\u1ed9t ph\u1ea7n c\u1ee7a Inheritance. Superclass l\u00e0 m\u1ed9t class, cho ph\u00e9p c\u00e1c subclass k\u1ebf th\u1eeba t\u1eeb superclass. V\u00ed d\u1ee5, n\u1ebfu Student l\u00e0 class b\u1eaft ngu\u1ed3n t\u1eeb l\u1edbp Person, th\u00ec Person s\u1ebd \u0111\u01b0\u1ee3c g\u1ecdi l\u00e0 superclass.\u00a0<\/span><\/p>\n<h3><b> Subclass l\u00e0 g\u00ec?<\/b><\/h3>\n<p><span style=\"font-weight: 400;\">Subclass l\u00e0 m\u1ed9t class k\u1ebf th\u1eeba c\u00e1c thu\u1ed9c t\u00ednh v\u00e0 h\u00e0nh vi t\u1eeb m\u1ed9t class kh\u00e1c, \u0111\u01b0\u1ee3c g\u1ecdi l\u00e0 superclass\u00a0 ho\u1eb7c parent class c\u1ee7a n\u00f3. Subclass m\u1edf r\u1ed9ng ho\u1eb7c chuy\u00ean bi\u1ec7t h\u00f3a ch\u1ee9c n\u0103ng superclass c\u1ee7a n\u00f3. V\u00ed d\u1ee5:<\/span><\/p>\n<pre><span style=\"font-weight: 400;\">class<\/span> <span style=\"font-weight: 400;\">Vehicle<\/span><span style=\"font-weight: 400;\">:<\/span>\r\n<span style=\"font-weight: 400;\">\u00a0 \u00a0 <\/span><span style=\"font-weight: 400;\">def<\/span> <span style=\"font-weight: 400;\">__init__<\/span><span style=\"font-weight: 400;\">(<\/span><span style=\"font-weight: 400;\">self<\/span><span style=\"font-weight: 400;\">, brand):<\/span>\r\n<span style=\"font-weight: 400;\">\u00a0 \u00a0 \u00a0 \u00a0 <\/span><span style=\"font-weight: 400;\">self<\/span><span style=\"font-weight: 400;\">.brand = brand<\/span>\r\n<span style=\"font-weight: 400;\"> \u00a0 \u00a0 <\/span>\r\n<span style=\"font-weight: 400;\">\u00a0 \u00a0 <\/span><span style=\"font-weight: 400;\">def<\/span> <span style=\"font-weight: 400;\">drive<\/span><span style=\"font-weight: 400;\">(<\/span><span style=\"font-weight: 400;\">self<\/span><span style=\"font-weight: 400;\">):<\/span>\r\n<span style=\"font-weight: 400;\">\u00a0 \u00a0 \u00a0 \u00a0 print(<\/span><span style=\"font-weight: 400;\">\"L\u00e1i xe\"<\/span><span style=\"font-weight: 400;\">, <\/span><span style=\"font-weight: 400;\">self<\/span><span style=\"font-weight: 400;\">.brand)<\/span>\r\n \r\n<span style=\"font-weight: 400;\">class<\/span> <span style=\"font-weight: 400;\">Car<\/span><span style=\"font-weight: 400;\">(<\/span><span style=\"font-weight: 400;\">Vehicle<\/span><span style=\"font-weight: 400;\">):<\/span>\r\n<span style=\"font-weight: 400;\">\u00a0 \u00a0 <\/span><span style=\"font-weight: 400;\">def<\/span> <span style=\"font-weight: 400;\">__init__<\/span><span style=\"font-weight: 400;\">(<\/span><span style=\"font-weight: 400;\">self<\/span><span style=\"font-weight: 400;\">, brand, model):<\/span>\r\n<span style=\"font-weight: 400;\">\u00a0 \u00a0 \u00a0 \u00a0 <\/span><span style=\"font-weight: 400;\">super<\/span><span style=\"font-weight: 400;\">().__init_<\/span><span style=\"font-weight: 400;\">_<\/span><span style=\"font-weight: 400;\">(brand)<\/span>\r\n<span style=\"font-weight: 400;\">\u00a0 \u00a0 \u00a0 \u00a0 <\/span><span style=\"font-weight: 400;\">self<\/span><span style=\"font-weight: 400;\">.model = model<\/span>\r\n<span style=\"font-weight: 400;\"> \u00a0 \u00a0 <\/span>\r\n<span style=\"font-weight: 400;\">\u00a0 \u00a0 <\/span><span style=\"font-weight: 400;\">def<\/span> <span style=\"font-weight: 400;\">honk<\/span><span style=\"font-weight: 400;\">(<\/span><span style=\"font-weight: 400;\">self<\/span><span style=\"font-weight: 400;\">):<\/span>\r\n<span style=\"font-weight: 400;\">\u00a0 \u00a0 \u00a0 \u00a0 print(<\/span><span style=\"font-weight: 400;\">\"Ti\u1ebfng k\u00e8n c\u1ee7a xe\"<\/span><span style=\"font-weight: 400;\">, <\/span><span style=\"font-weight: 400;\">self<\/span><span style=\"font-weight: 400;\">.brand, <\/span><span style=\"font-weight: 400;\">self<\/span><span style=\"font-weight: 400;\">.model)<\/span>\r\n \r\n<span style=\"font-weight: 400;\"># T\u1ea1o m\u1ed9t instance c\u1ee7a class Car<\/span>\r\n<span style=\"font-weight: 400;\">my_car = Car(<\/span><span style=\"font-weight: 400;\">\"Toyota\"<\/span><span style=\"font-weight: 400;\">, <\/span><span style=\"font-weight: 400;\">\"Camry\"<\/span><span style=\"font-weight: 400;\">)<\/span>\r\n<span style=\"font-weight: 400;\">my_car.drive()\u00a0 <\/span><span style=\"font-weight: 400;\"># Output: L\u00e1i xe Toyota<\/span>\r\n<span style=\"font-weight: 400;\">my_car.honk() \u00a0 <\/span><span style=\"font-weight: 400;\"># Output: Ti\u1ebfng k\u00e8n c\u1ee7a xe Toyota Camry<\/span><\/pre>\n<p><span style=\"font-weight: 400;\">Trong v\u00ed d\u1ee5 n\u00e0y, <\/span><span style=\"font-weight: 400;\">&#8216;Car&#8217; <\/span><span style=\"font-weight: 400;\">l\u00e0 subclass c\u1ee7a <\/span><span style=\"font-weight: 400;\">&#8216;Vehicle&#8217;<\/span><span style=\"font-weight: 400;\">. N\u00f3 k\u1ebf th\u1eeba ph\u01b0\u01a1ng th\u1ee9c <\/span><span style=\"font-weight: 400;\">&#8216;drive()&#8217; <\/span><span style=\"font-weight: 400;\">t\u1eeb <\/span><span style=\"font-weight: 400;\">Vehicle<\/span><span style=\"font-weight: 400;\"> v\u00e0 th\u00eam ph\u01b0\u01a1ng th\u1ee9c<\/span><span style=\"font-weight: 400;\"> &#8216;honk()&#8217;<\/span><span style=\"font-weight: 400;\"> c\u1ee7a class n\u00e0y. C\u00e1c th\u1ec3 hi\u1ec7n c\u1ee7a <\/span><span style=\"font-weight: 400;\">Car<\/span><span style=\"font-weight: 400;\"> c\u00f3 th\u1ec3 truy c\u1eadp v\u00e0o c\u1ea3 ph\u01b0\u01a1ng th\u1ee9c c\u1ee7a superclass v\u00e0 subclass.<\/span><\/p>\n<h3><b> Method overloading l\u00e0 g\u00ec?<\/b><\/h3>\n<p><span style=\"font-weight: 400;\">Method overloading (n\u1ea1p ch\u1ed3ng h\u00e0m) l\u00e0 m\u1ed9t t\u00ednh n\u0103ng trong OOP cho ph\u00e9p m\u1ed9t class c\u00f3 nhi\u1ec1u ph\u01b0\u01a1ng th\u1ee9c c\u00f3 c\u00f9ng t\u00ean nh\u01b0ng kh\u00e1c nhau v\u1ec1 tham s\u1ed1 ho\u1eb7c ki\u1ec3u tham s\u1ed1. \u0110i\u1ec1u n\u00e0y cho ph\u00e9p c\u00e1c Developer x\u00e1c \u0111\u1ecbnh nhi\u1ec1u phi\u00ean b\u1ea3n kh\u00e1c nhau c\u1ee7a m\u1ed9t k\u1ef9 thu\u1eadt, m\u1ed7i phi\u00ean b\u1ea3n \u0111\u01b0\u1ee3c thi\u1ebft k\u1ebf ri\u00eang \u0111\u1ec3 ch\u1ea5p nh\u1eadn c\u00e1c lo\u1ea1i ho\u1eb7c s\u1ed1 l\u01b0\u1ee3ng tham s\u1ed1 kh\u00e1c nhau. Khi m\u1ed9t ph\u01b0\u01a1ng th\u1ee9c \u0111\u01b0\u1ee3c g\u1ecdi, phi\u00ean b\u1ea3n th\u00edch h\u1ee3p s\u1ebd \u0111\u01b0\u1ee3c ch\u1ecdn d\u1ef1a tr\u00ean c\u00e1c tham s\u1ed1 \u0111\u01b0\u1ee3c cung c\u1ea5p.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">V\u00ed d\u1ee5, h\u00e3y xem x\u00e9t Calculator class c\u00f3 ph\u01b0\u01a1ng th\u1ee9c add():<\/span><\/p>\n<p><span style=\"font-weight: 400;\">V\u00ed d\u1ee5 v\u1edbi Java:<\/span><\/p>\n<pre><span style=\"font-weight: 400;\">public<\/span> <span style=\"font-weight: 400;\">class<\/span> <span style=\"font-weight: 400;\">Calculator<\/span><span style=\"font-weight: 400;\"> {<\/span>\r\n<span style=\"font-weight: 400;\">\u00a0 \u00a0 <\/span><span style=\"font-weight: 400;\">public<\/span> <span style=\"font-weight: 400;\">int<\/span> <span style=\"font-weight: 400;\">add<\/span><span style=\"font-weight: 400;\">(<\/span><span style=\"font-weight: 400;\">int<\/span><span style=\"font-weight: 400;\"> num1, <\/span><span style=\"font-weight: 400;\">int<\/span><span style=\"font-weight: 400;\"> num2) {<\/span>\r\n<span style=\"font-weight: 400;\">\u00a0 \u00a0 \u00a0 \u00a0 <\/span><span style=\"font-weight: 400;\">return<\/span><span style=\"font-weight: 400;\"> num1 + num2;<\/span>\r\n<span style=\"font-weight: 400;\">\u00a0 \u00a0 }<\/span>\r\n \r\n<span style=\"font-weight: 400;\">\u00a0 \u00a0 <\/span><span style=\"font-weight: 400;\">public<\/span> <span style=\"font-weight: 400;\">double<\/span> <span style=\"font-weight: 400;\">add<\/span><span style=\"font-weight: 400;\">(<\/span><span style=\"font-weight: 400;\">double<\/span><span style=\"font-weight: 400;\"> num1, <\/span><span style=\"font-weight: 400;\">double<\/span><span style=\"font-weight: 400;\"> num2) {<\/span>\r\n<span style=\"font-weight: 400;\">\u00a0 \u00a0 \u00a0 \u00a0 <\/span><span style=\"font-weight: 400;\">return<\/span><span style=\"font-weight: 400;\"> num1 + num2;<\/span>\r\n<span style=\"font-weight: 400;\">\u00a0 \u00a0 }<\/span>\r\n<span style=\"font-weight: 400;\">}<\/span><\/pre>\n<p><span style=\"font-weight: 400;\">Trong v\u00ed d\u1ee5 n\u00e0y, ph\u01b0\u01a1ng th\u1ee9c <\/span><span style=\"font-weight: 400;\">add()<\/span><span style=\"font-weight: 400;\">\u0111\u01b0\u1ee3c n\u1ea1p ch\u1ed3ng \u0111\u1ec3 ch\u1ea5p nh\u1eadn c\u00e1c tham s\u1ed1 l\u00e0 s\u1ed1 nguy\u00ean v\u00e0 s\u1ed1 th\u1ef1c. T\u00f9y thu\u1ed9c v\u00e0o vi\u1ec7c gi\u00e1 tr\u1ecb s\u1ed1 nguy\u00ean hay s\u1ed1 \u0111\u00f4i \u0111\u01b0\u1ee3c truy\u1ec1n l\u00e0m \u0111\u1ed1i s\u1ed1, phi\u00ean b\u1ea3n t\u01b0\u01a1ng \u1ee9ng c\u1ee7a ph\u01b0\u01a1ng th\u1ee9c <\/span><span style=\"font-weight: 400;\">add()<\/span><span style=\"font-weight: 400;\"> s\u1ebd \u0111\u01b0\u1ee3c g\u1ecdi. \u0110i\u1ec1u n\u00e0y mang l\u1ea1i s\u1ef1 linh ho\u1ea1t v\u00e0 ti\u1ec7n l\u1ee3i khi l\u00e0m vi\u1ec7c v\u1edbi c\u00e1c lo\u1ea1i d\u1eef li\u1ec7u kh\u00e1c nhau.<\/span><\/p>\n<h3><b> C\u00e1c tr\u00ecnh s\u1eeda \u0111\u1ed5i quy\u1ec1n truy c\u1eadp l\u00e0 g\u00ec?<\/b><\/h3>\n<p><span style=\"font-weight: 400;\">Access modifier hay c\u00f2n g\u1ecdi l\u00e0 tr\u00ecnh s\u1eeda \u0111\u1ed5i truy c\u1eadp l\u00e0 c\u00e1c t\u1eeb kh\u00f3a \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng trong ng\u00f4n ng\u1eef l\u1eadp tr\u00ecnh h\u01b0\u1edbng \u0111\u1ed1i t\u01b0\u1ee3ng \u0111\u1ec3 ki\u1ec3m so\u00e1t kh\u1ea3 n\u0103ng hi\u1ec3n th\u1ecb v\u00e0 kh\u1ea3 n\u0103ng truy c\u1eadp c\u1ee7a c\u00e1c class, ph\u01b0\u01a1ng th\u1ee9c v\u00e0 c\u00e1c th\u00e0nh ph\u1ea7n kh\u00e1c trong m\u1ed9t ch\u01b0\u01a1ng tr\u00ecnh. Access modifier x\u00e1c \u0111\u1ecbnh c\u00e1ch c\u00e1c th\u00e0nh ph\u1ea7n n\u00e0y c\u00f3 th\u1ec3 \u0111\u01b0\u1ee3c truy c\u1eadp t\u1eeb c\u00e1c ph\u1ea7n kh\u00e1c nhau c\u1ee7a ch\u01b0\u01a1ng tr\u00ecnh ho\u1eb7c b\u00ean ngo\u00e0i c\u00e1c m\u00f4-\u0111un. C\u00e1c access modifiers ch\u00ednh bao g\u1ed3m:<\/span><\/p>\n<ul>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">Public: Cho ph\u00e9p c\u00e1c th\u00e0nh vi\u00ean c\u00f3 th\u1ec3 \u0111\u01b0\u1ee3c truy c\u1eadp t\u1eeb m\u1ecdi v\u1ecb tr\u00ed c\u1ee7a ch\u01b0\u01a1ng tr\u00ecnh.<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">Private: Ch\u1ec9 cho ph\u00e9p truy c\u1eadp trong ph\u1ea1m vi class hi\u1ec7n t\u1ea1i., ng\u0103n ch\u1eb7n quy\u1ec1n truy c\u1eadp t\u1eeb b\u00ean ngo\u00e0i.<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">Protected: C\u1ea5p quy\u1ec1n truy c\u1eadp cho c\u00e1c th\u00e0nh ph\u1ea7n trong c\u00f9ng m\u1ed9t class v\u00e0 c\u00e1c subclass c\u1ee7a n\u00f3, nh\u01b0ng kh\u00f4ng c\u1ea5p quy\u1ec1n truy c\u1eadp t\u1eeb b\u00ean ngo\u00e0i.<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">Internal: Gi\u1edbi h\u1ea1n quy\u1ec1n truy c\u1eadp trong c\u00f9ng m\u1ed9t assembly ho\u1eb7c m\u00f4-\u0111un.<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">Protected Internal: K\u1ebft h\u1ee3p gi\u1eefa protected v\u00e0 internal, cho ph\u00e9p truy c\u1eadp trong c\u00f9ng m\u1ed9t assembly ho\u1eb7c t\u1eeb c\u00e1c subclass, b\u1ea5t k\u1ec3 c\u00f3 c\u00f9ng assembly hay kh\u00f4ng.<\/span><\/li>\n<\/ul>\n<p><span style=\"font-weight: 400;\">C\u00e1c access modifier l\u00e0 m\u1ed9t c\u00f4ng c\u1ee5 m\u1ea1nh m\u1ebd trong OOP, gi\u00fap c\u00e1c l\u1eadp tr\u00ecnh vi\u00ean ki\u1ec3m so\u00e1t quy\u1ec1n truy c\u1eadp v\u00e0o c\u00e1c th\u00e0nh ph\u1ea7n c\u1ee7a ch\u01b0\u01a1ng tr\u00ecnh, b\u1ea3o v\u1ec7 d\u1eef li\u1ec7u v\u00e0 t\u0103ng t\u00ednh b\u1ea3o m\u1eadt, \u0111\u1ed3ng th\u1eddi gi\u00fap t\u1ea1o ra code r\u00f5 r\u00e0ng, d\u1ec5 b\u1ea3o tr\u00ec v\u00e0 m\u1edf r\u1ed9ng.<\/span><\/p>\n<h3><b> S\u1ef1 kh\u00e1c bi\u1ec7t gi\u1eefa overloading v\u00e0 overriding nh\u01b0 th\u1ebf n\u00e0o<\/b><span style=\"font-weight: 400;\">?<\/span><\/h3>\n<p><span style=\"font-weight: 400;\">Overloading l\u00e0 hai ho\u1eb7c nhi\u1ec1u ph\u01b0\u01a1ng th\u1ee9c c\u00f3 c\u00f9ng t\u00ean nh\u01b0ng tham s\u1ed1 kh\u00e1c nhau. N\u00f3 \u0111\u01b0\u1ee3c gi\u1ea3i quy\u1ebft trong compile-time. Trong khi \u0111\u00f3, Overriding l\u00e0 m\u1ed9t kh\u00e1i ni\u1ec7m OOP cho ph\u00e9p c\u00e1c subclass c\u00f3 m\u1ed9t tri\u1ec3n khai c\u1ee5 th\u1ec3 c\u1ee7a m\u1ed9t ph\u01b0\u01a1ng th\u1ee9c \u0111\u00e3 \u0111\u01b0\u1ee3c parent class c\u1ee7a n\u00f3 cung c\u1ea5p. Overriding \u0111\u01b0\u1ee3c gi\u1ea3i quy\u1ebft trong runtime, \u0111\u01b0\u1ee3c tri\u1ec3n khai v\u1edbi s\u1ef1 tr\u1ee3 gi\u00fap c\u1ee7a c\u00e1c Virtual function (h\u00e0m \u1ea3o).<\/span><\/p>\n<h2><span class=\"ez-toc-section\" id=\"Tong_ket_Cau_hoi_phong_van_OOP_Phan_1\"><\/span><b>T\u1ed5ng k\u1ebft C\u00e2u h\u1ecfi ph\u1ecfng v\u1ea5n OOP (Ph\u1ea7n 1)<\/b><span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p><span style=\"font-weight: 400;\">N\u1eafm v\u1eefng 25 c\u00e2u h\u1ecfi ph\u1ecfng v\u1ea5n OOP tr\u00ean \u0111\u1ed3ng ngh\u0129a b\u1ea1n n\u1eafm ch\u1eafc k\u1ef9 n\u0103ng c\u01a1 b\u1ea3n v\u1ec1 OOP, t\u1ef1 tin chinh ph\u1ee5c c\u00e1c v\u1ecb tr\u00ed \u0111\u1ea7u v\u00e0o v\u00e0 c\u1ea7n \u00edt kinh nghi\u1ec7m. \u0110\u1ec3 c\u00f3 c\u01a1 h\u1ed9i s\u1edf h\u1eefu v\u1ecb tr\u00ed c\u1ea5p cao v\u1ec1 OOP, b\u1ea1n c\u1ea7n trang b\u1ecb cho m\u00ecnh nhi\u1ec1u ki\u1ebfn th\u1ee9c chuy\u00ean ng\u00e0nh h\u01a1n n\u1eefa v\u00e0 k\u1ebft h\u1ee3p v\u1edbi kinh nghi\u1ec7m th\u1ef1c t\u1ebf nhi\u1ec1u n\u0103m.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">\u1ede <a href=\"https:\/\/itviec.com\/blog\/cau-hoi-phong-van-oop-phan-2\/\" target=\"_blank\" rel=\"noopener\"><strong>Ph\u1ea7n 2<\/strong><\/a>, ITviec s\u1ebd chia s\u1ebb \u0111\u1ebfn b\u1ea1n c\u00e1c c\u00e2u h\u1ecfi ph\u1ecfng v\u1ea5n OOP c\u1ea5p \u0111\u1ed9 n\u00e2ng cao c\u0169ng nh\u01b0 c\u00e1c c\u00e2u h\u1ecfi th\u1ef1c h\u00e0nh. C\u00f9ng theo d\u00f5i \u0111\u1ec3 n\u00e2ng cao k\u1ef9 n\u0103ng l\u1eadp tr\u00ecnh OOP nh\u00e9.<\/span><\/p>\n","protected":false},"excerpt":{"rendered":"<p>L\u1eadp tr\u00ecnh h\u01b0\u1edbng \u0111\u1ed1i t\u01b0\u1ee3ng (OOP) l\u00e0 m\u1ed9t trong nh\u1eefng k\u1ef9 n\u0103ng c\u1ed1t l\u00f5i m\u00e0 c\u00e1c Software Developer c\u1ea7n ph\u1ea3i n\u1eafm v\u1eefng. \u0110\u1ec3 \u0111\u00e1nh gi\u00e1 k\u1ef9 n\u0103ng OOP c\u1ee7a \u1ee9ng vi\u00ean, c\u00e1c nh\u00e0 tuy\u1ec3n d\u1ee5ng th\u01b0\u1eddng \u0111\u01b0a ra nh\u1eefng c\u00e2u h\u1ecfi ph\u1ecfng v\u1ea5n r\u1ea5t \u0111a d\u1ea1ng. H\u00e3y c\u00f9ng ITviec kh\u00e1m ph\u00e1 50 c\u00e2u h\u1ecfi ph\u1ecfng [&hellip;]<\/p>\n","protected":false},"author":205,"featured_media":80431,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"_gspb_post_css":"","footnotes":""},"categories":[109,99,94],"tags":[],"class_list":["post-80175","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-chuyen-mon-it","category-developer","category-su-nghiep-it"],"blocksy_meta":[],"acf":[],"yoast_head":"<!-- This site is optimized with the Yoast SEO Premium plugin v26.8 (Yoast SEO v27.7) - https:\/\/yoast.com\/product\/yoast-seo-premium-wordpress\/ -->\n<title>Top 50+ c\u00e2u h\u1ecfi ph\u1ecfng v\u1ea5n OOP v\u00e0 tr\u1ea3 l\u1eddi m\u1edbi nh\u1ea5t (Ph\u1ea7n 1) - ITviec Blog<\/title>\n<meta name=\"description\" content=\"Kh\u00e1m ph\u00e1 50 c\u00e2u h\u1ecfi ph\u1ecfng v\u1ea5n OOP th\u01b0\u1eddng g\u1eb7p, t\u1eeb c\u01a1 b\u1ea3n \u0111\u1ebfn n\u00e2ng cao, c\u00f9ng c\u00e2u tr\u1ea3 l\u1eddi chu\u1ea9n x\u00e1c \u0111\u1ec3 th\u00e0nh c\u00f4ng trong c\u00e1c bu\u1ed5i ph\u1ecfng v\u1ea5n.\" \/>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/itviec.com\/blog\/cau-hoi-phong-van-oop-phan-1\/\" \/>\n<meta property=\"og:locale\" content=\"vi_VN\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"Top 50+ c\u00e2u h\u1ecfi ph\u1ecfng v\u1ea5n OOP v\u00e0 tr\u1ea3 l\u1eddi m\u1edbi nh\u1ea5t (Ph\u1ea7n 1)\" \/>\n<meta property=\"og:description\" content=\"L\u1eadp tr\u00ecnh h\u01b0\u1edbng \u0111\u1ed1i t\u01b0\u1ee3ng (OOP) l\u00e0 m\u1ed9t trong nh\u1eefng k\u1ef9 n\u0103ng c\u1ed1t l\u00f5i m\u00e0 c\u00e1c Software Developer c\u1ea7n ph\u1ea3i n\u1eafm v\u1eefng. \u0110\u1ec3 \u0111\u00e1nh gi\u00e1 k\u1ef9 n\u0103ng OOP c\u1ee7a \u1ee9ng vi\u00ean, c\u00e1c\" \/>\n<meta property=\"og:url\" content=\"https:\/\/itviec.com\/blog\/cau-hoi-phong-van-oop-phan-1\/\" \/>\n<meta property=\"og:site_name\" content=\"ITviec Blog\" \/>\n<meta property=\"article:publisher\" content=\"https:\/\/www.facebook.com\/ITviec\" \/>\n<meta property=\"article:published_time\" content=\"2024-10-21T09:47:59+00:00\" \/>\n<meta property=\"og:image\" content=\"https:\/\/itviec.com\/blog\/wp-content\/uploads\/2024\/10\/Top-cau-hoi-phong-van-OOP-pho-bien-nhat-Phan-1-vippro.jpg\" \/>\n\t<meta property=\"og:image:width\" content=\"1500\" \/>\n\t<meta property=\"og:image:height\" content=\"790\" \/>\n\t<meta property=\"og:image:type\" content=\"image\/jpeg\" \/>\n<meta name=\"author\" content=\"H\u00e0 My\" \/>\n<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n<meta name=\"twitter:creator\" content=\"@ITviec\" \/>\n<meta name=\"twitter:site\" content=\"@ITviec\" \/>\n<meta name=\"twitter:label1\" content=\"\u0110\u01b0\u1ee3c vi\u1ebft b\u1edfi\" \/>\n\t<meta name=\"twitter:data1\" content=\"H\u00e0 My\" \/>\n\t<meta name=\"twitter:label2\" content=\"\u01af\u1edbc t\u00ednh th\u1eddi gian \u0111\u1ecdc\" \/>\n\t<meta name=\"twitter:data2\" content=\"22 ph\u00fat\" \/>\n<!-- \/ Yoast SEO Premium plugin. -->","yoast_head_json":{"title":"Top 50+ c\u00e2u h\u1ecfi ph\u1ecfng v\u1ea5n OOP v\u00e0 tr\u1ea3 l\u1eddi m\u1edbi nh\u1ea5t (Ph\u1ea7n 1) - 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