{"id":27441,"date":"2025-04-23T15:13:23","date_gmt":"2025-04-23T08:13:23","guid":{"rendered":"https:\/\/interdata.vn\/blog\/?p=27441"},"modified":"2025-04-23T16:28:44","modified_gmt":"2025-04-23T09:28:44","slug":"function-ham-la-gi","status":"publish","type":"post","link":"https:\/\/interdata.vn\/blog\/function-ham-la-gi\/","title":{"rendered":"Function (H\u00e0m) l\u00e0 g\u00ec trong L\u1eadp tr\u00ecnh? To\u00e0n t\u1eadp t\u1eeb A-Z"},"content":{"rendered":"<div id=\"ez-toc-container\" class=\"ez-toc-v2_0_85 counter-hierarchy ez-toc-counter ez-toc-white ez-toc-container-direction\">\n<div class=\"ez-toc-title-container\">\n<p class=\"ez-toc-title\" style=\"cursor:inherit\">N\u1ed8I DUNG<\/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 eztoc-toggle-hide-by-default' ><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-1\" href=\"https:\/\/interdata.vn\/blog\/function-ham-la-gi\/#Function-Ham-la-gi\" >Function (H\u00e0m) 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:\/\/interdata.vn\/blog\/function-ham-la-gi\/#Tai-sao-Ham-Function-lai-quan-trong-trong-lap-trinh\" >T\u1ea1i sao H\u00e0m (Function) l\u1ea1i quan tr\u1ecdng trong l\u1eadp tr\u00ecnh?<\/a><ul class='ez-toc-list-level-3' ><li class='ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-3\" href=\"https:\/\/interdata.vn\/blog\/function-ham-la-gi\/#Tai-su-dung-Code-Viet-mot-lan-dung-moi-noi\" >T\u00e1i s\u1eed d\u1ee5ng Code: Vi\u1ebft m\u1ed9t l\u1ea7n, d\u00f9ng m\u1ecdi n\u01a1i<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-4\" href=\"https:\/\/interdata.vn\/blog\/function-ham-la-gi\/#Tang-tinh-Module-va-to-chuc-Code\" >T\u0103ng t\u00ednh Module v\u00e0 t\u1ed5 ch\u1ee9c Code<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-5\" href=\"https:\/\/interdata.vn\/blog\/function-ham-la-gi\/#De-dang-bao-tri-va-sua-loi\" >D\u1ec5 d\u00e0ng b\u1ea3o tr\u00ec v\u00e0 s\u1eeda l\u1ed7i<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-6\" href=\"https:\/\/interdata.vn\/blog\/function-ham-la-gi\/#Truu-tuong-hoa-Abstraction-Che-giau-su-phuc-tap\" >Tr\u1eebu t\u01b0\u1ee3ng h\u00f3a (Abstraction): Che gi\u1ea5u s\u1ef1 ph\u1ee9c t\u1ea1p<\/a><\/li><\/ul><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-7\" href=\"https:\/\/interdata.vn\/blog\/function-ham-la-gi\/#Cau-truc-co-ban-cua-mot-Ham-Function-Structure\" >C\u1ea5u tr\u00fac c\u01a1 b\u1ea3n c\u1ee7a m\u1ed9t H\u00e0m (Function Structure)<\/a><ul class='ez-toc-list-level-3' ><li class='ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-8\" href=\"https:\/\/interdata.vn\/blog\/function-ham-la-gi\/#Khai-bao-Dinh-nghia-Ham-Function-Declaration-Definition\" >Khai b\u00e1o \/ \u0110\u1ecbnh ngh\u0129a H\u00e0m (Function Declaration \/ Definition)<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-9\" href=\"https:\/\/interdata.vn\/blog\/function-ham-la-gi\/#Ten-Ham-Function-Name-Cach-dat-ten-noi-len-tat-ca\" >T\u00ean H\u00e0m (Function Name): C\u00e1ch \u0111\u1eb7t t\u00ean n\u00f3i l\u00ean t\u1ea5t c\u1ea3<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-10\" href=\"https:\/\/interdata.vn\/blog\/function-ham-la-gi\/#Tham-so-Parameters-%E2%80%9CNguyen-lieu%E2%80%9D-dau-vao-cua-Ham\" >Tham s\u1ed1 (Parameters): &#8220;Nguy\u00ean li\u1ec7u&#8221; \u0111\u1ea7u v\u00e0o c\u1ee7a H\u00e0m<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-11\" href=\"https:\/\/interdata.vn\/blog\/function-ham-la-gi\/#Doi-so-Arguments-Gia-tri-thuc-te-truyen-vao-Ham\" >\u0110\u1ed1i s\u1ed1 (Arguments): Gi\u00e1 tr\u1ecb th\u1ef1c t\u1ebf truy\u1ec1n v\u00e0o H\u00e0m<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-12\" href=\"https:\/\/interdata.vn\/blog\/function-ham-la-gi\/#Than-Ham-Function-Body-%E2%80%9CNha-may%E2%80%9D-xu-ly-logic\" >Th\u00e2n H\u00e0m (Function Body): &#8220;Nh\u00e0 m\u00e1y&#8221; x\u1eed l\u00fd logic<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-13\" href=\"https:\/\/interdata.vn\/blog\/function-ham-la-gi\/#Gia-tri-tra-ve-Return-Value-Ket-qua-Ham-tao-ra\" >Gi\u00e1 tr\u1ecb tr\u1ea3 v\u1ec1 (Return Value): K\u1ebft qu\u1ea3 H\u00e0m t\u1ea1o ra<\/a><\/li><\/ul><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-14\" href=\"https:\/\/interdata.vn\/blog\/function-ham-la-gi\/#Cach-khai-bao-va-goi-Ham-Vi-du-thuc-te\" >C\u00e1ch khai b\u00e1o v\u00e0 g\u1ecdi H\u00e0m: V\u00ed d\u1ee5 th\u1ef1c t\u1ebf<\/a><ul class='ez-toc-list-level-3' ><li class='ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-15\" href=\"https:\/\/interdata.vn\/blog\/function-ham-la-gi\/#Vi-du-Khai-bao-Ham-don-gian\" >V\u00ed d\u1ee5 Khai b\u00e1o H\u00e0m \u0111\u01a1n gi\u1ea3n<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-16\" href=\"https:\/\/interdata.vn\/blog\/function-ham-la-gi\/#Vi-du-Goi-Ham-tuong-ung\" >V\u00ed d\u1ee5 G\u1ecdi H\u00e0m t\u01b0\u01a1ng \u1ee9ng<\/a><\/li><\/ul><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-17\" href=\"https:\/\/interdata.vn\/blog\/function-ham-la-gi\/#Phan-loai-Ham-co-ban-thuong-gap\" >Ph\u00e2n lo\u1ea1i H\u00e0m c\u01a1 b\u1ea3n th\u01b0\u1eddng g\u1eb7p<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-18\" href=\"https:\/\/interdata.vn\/blog\/function-ham-la-gi\/#Meo-su-dung-Ham-hieu-qua-cho-nguoi-moi-bat-dau\" >M\u1eb9o s\u1eed d\u1ee5ng H\u00e0m hi\u1ec7u qu\u1ea3 cho ng\u01b0\u1eddi m\u1edbi b\u1eaft \u0111\u1ea7u<\/a><\/li><\/ul><\/nav><\/div>\n\n<p data-start=\"640\" data-end=\"943\">Mu\u1ed1n vi\u1ebft code kh\u00f4ng ch\u1ec9 ch\u1ea1y \u0111\u01b0\u1ee3c m\u00e0 c\u00f2n g\u1ecdn g\u00e0ng, d\u1ec5 b\u1ea3o tr\u00ec v\u00e0 t\u00e1i s\u1eed d\u1ee5ng hi\u1ec7u qu\u1ea3? Hi\u1ec3u r\u00f5 v\u1ec1 <strong>function (h\u00e0m)<\/strong> l\u00e0 \u0111i\u1ec1u b\u1eaft bu\u1ed9c! B\u00e0i vi\u1ebft &#8220;to\u00e0n t\u1eadp&#8221; n\u00e0y s\u1ebd d\u1eabn d\u1eaft b\u1ea1n \u0111i t\u1eeb \u0111\u1ecbnh ngh\u0129a c\u01a1 b\u1ea3n <strong>h\u00e0m l\u00e0 g\u00ec<\/strong>, ph\u00e2n t\u00edch s\u00e2u c\u00e1c l\u1ee3i \u00edch thi\u1ebft th\u1ef1c, m\u1ed5 x\u1ebb t\u1eebng th\u00e0nh ph\u1ea7n c\u1ea5u tr\u00fac, h\u01b0\u1edbng d\u1eabn c\u00e1ch s\u1eed d\u1ee5ng qua v\u00ed d\u1ee5 tr\u1ef1c quan v\u00e0 cung c\u1ea5p c\u00e1c l\u1eddi khuy\u00ean gi\u00e1 tr\u1ecb cho ng\u01b0\u1eddi m\u1edbi b\u1eaft \u0111\u1ea7u.<\/p>\n<h2><span class=\"ez-toc-section\" id=\"Function-Ham-la-gi\"><\/span>Function (H\u00e0m) l\u00e0 g\u00ec?<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p><strong>H\u00e0m (Function) v\u1ec1 c\u01a1 b\u1ea3n l\u00e0 m\u1ed9t kh\u1ed1i m\u00e3 l\u1ec7nh \u0111\u01b0\u1ee3c \u0111\u1eb7t t\u00ean, d\u00f9ng \u0111\u1ec3 th\u1ef1c hi\u1ec7n m\u1ed9t nhi\u1ec7m v\u1ee5 c\u1ee5 th\u1ec3 v\u00e0 \u0111\u1ed9c l\u1eadp.<\/strong> N\u00f3 gi\u1ed1ng nh\u01b0 m\u1ed9t &#8220;ch\u01b0\u01a1ng tr\u00ecnh con&#8221; m\u00e0 b\u1ea1n c\u00f3 th\u1ec3 t\u1ea1o ra \u0111\u1ec3 gi\u1ea3i quy\u1ebft m\u1ed9t ph\u1ea7n c\u00f4ng vi\u1ec7c n\u00e0o \u0111\u00f3 trong ch\u01b0\u01a1ng tr\u00ecnh ch\u00ednh c\u1ee7a m\u00ecnh.<\/p>\n<p>H\u00e3y h\u00ecnh dung h\u00e0m nh\u01b0 m\u1ed9t <strong>c\u00f4ng th\u1ee9c n\u1ea5u \u0103n<\/strong> \u0111\u01b0\u1ee3c \u0111\u00f3ng g\u00f3i c\u1ea9n th\u1eadn. B\u1ea1n \u0111\u1eb7t t\u00ean cho c\u00f4ng th\u1ee9c \u0111\u00f3 (v\u00ed d\u1ee5: <code>congThucPhaCafe<\/code>), li\u1ec7t k\u00ea c\u00e1c &#8220;nguy\u00ean li\u1ec7u&#8221; c\u1ea7n thi\u1ebft (v\u00ed d\u1ee5: b\u1ed9t cafe, n\u01b0\u1edbc n\u00f3ng, \u0111\u01b0\u1eddng &#8211; \u0111\u00e2y l\u00e0 c\u00e1c <strong><a href=\"https:\/\/interdata.vn\/blog\/tham-so-parameter-la-gi\/\">tham s\u1ed1<\/a><\/strong>). Khi n\u00e0o mu\u1ed1n u\u1ed1ng cafe, b\u1ea1n ch\u1ec9 c\u1ea7n g\u1ecdi t\u00ean c\u00f4ng th\u1ee9c n\u00e0y ra v\u00e0 th\u1ef1c hi\u1ec7n theo.<\/p>\n<p>T\u01b0\u01a1ng t\u1ef1, trong <a href=\"https:\/\/interdata.vn\/blog\/lap-trinh-la-gi\/\">l\u1eadp tr\u00ecnh<\/a>, khi b\u1ea1n \u0111\u1ecbnh ngh\u0129a m\u1ed9t h\u00e0m, b\u1ea1n \u0111\u1eb7t cho n\u00f3 m\u1ed9t c\u00e1i t\u00ean v\u00e0 ch\u1ec9 \u0111\u1ecbnh nh\u1eefng g\u00ec n\u00f3 c\u1ea7n l\u00e0m. Sau \u0111\u00f3, b\u1ea5t c\u1ee9 khi n\u00e0o b\u1ea1n c\u1ea7n th\u1ef1c hi\u1ec7n t\u00e1c v\u1ee5 \u0111\u00f3, b\u1ea1n ch\u1ec9 c\u1ea7n <strong>g\u1ecdi t\u00ean h\u00e0m<\/strong> thay v\u00ec ph\u1ea3i vi\u1ebft l\u1ea1i to\u00e0n b\u1ed9 c\u00e1c b\u01b0\u1edbc th\u1ef1c hi\u1ec7n t\u1eeb \u0111\u1ea7u.<\/p>\n<p>Vi\u1ec7c n\u00e0y gi\u00fap <strong>t\u1ed5 ch\u1ee9c <a href=\"https:\/\/interdata.vn\/blog\/source-code-la-gi\/\">m\u00e3 ngu\u1ed3n<\/a> (code)<\/strong> c\u1ee7a b\u1ea1n tr\u1edf n\u00ean c\u1ef1c k\u1ef3 g\u1ecdn g\u00e0ng v\u00e0 logic. Thay v\u00ec m\u1ed9t ch\u01b0\u01a1ng tr\u00ecnh d\u00e0i d\u1eb1ng d\u1eb7c kh\u00f3 ki\u1ec3m so\u00e1t, b\u1ea1n s\u1ebd c\u00f3 nh\u1eefng kh\u1ed1i ch\u1ee9c n\u0103ng nh\u1ecf, r\u00f5 r\u00e0ng, m\u1ed7i kh\u1ed1i \u0111\u1ea3m nhi\u1ec7m m\u1ed9t c\u00f4ng vi\u1ec7c ri\u00eang bi\u1ec7t, gi\u00fap t\u1ed5ng th\u1ec3 ch\u01b0\u01a1ng tr\u00ecnh d\u1ec5 hi\u1ec3u v\u00e0 qu\u1ea3n l\u00fd h\u01a1n r\u1ea5t nhi\u1ec1u.<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/interdata.vn\/blog\/wp-content\/uploads\/2025\/04\/Function-ham.jpg\" alt=\"Function (h\u00e0m)\" width=\"750\" height=\"500\" class=\"aligncenter size-full wp-image-27449\" title=\"\" srcset=\"https:\/\/interdata.vn\/blog\/wp-content\/uploads\/2025\/04\/Function-ham.jpg 750w, https:\/\/interdata.vn\/blog\/wp-content\/uploads\/2025\/04\/Function-ham-300x200.jpg 300w\" sizes=\"auto, (max-width: 750px) 100vw, 750px\" \/><\/p>\n<h2><span class=\"ez-toc-section\" id=\"Tai-sao-Ham-Function-lai-quan-trong-trong-lap-trinh\"><\/span>T\u1ea1i sao H\u00e0m (Function) l\u1ea1i quan tr\u1ecdng trong l\u1eadp tr\u00ecnh?<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>V\u1eady t\u1ea1i sao h\u1ea7u h\u1ebft m\u1ecdi <a href=\"https:\/\/interdata.vn\/blog\/ngon-ngu-lap-trinh-la-gi\/\">ng\u00f4n ng\u1eef l\u1eadp tr\u00ecnh<\/a> \u0111\u1ec1u c\u00f3 kh\u00e1i ni\u1ec7m h\u00e0m v\u00e0 t\u1ea1i sao ch\u00fang l\u1ea1i \u0111\u01b0\u1ee3c coi l\u00e0 n\u1ec1n t\u1ea3ng? H\u00e0m mang l\u1ea1i v\u00f4 s\u1ed1 l\u1ee3i \u00edch, \u0111\u1eb7c bi\u1ec7t l\u00e0 khi x\u00e2y d\u1ef1ng c\u00e1c \u1ee9ng d\u1ee5ng ph\u1ee9c t\u1ea1p. D\u01b0\u1edbi \u0111\u00e2y l\u00e0 nh\u1eefng l\u00fd do ch\u00ednh khi\u1ebfn h\u00e0m tr\u1edf n\u00ean kh\u00f4ng th\u1ec3 thi\u1ebfu:<\/p>\n<h3><span class=\"ez-toc-section\" id=\"Tai-su-dung-Code-Viet-mot-lan-dung-moi-noi\"><\/span>T\u00e1i s\u1eed d\u1ee5ng Code: Vi\u1ebft m\u1ed9t l\u1ea7n, d\u00f9ng m\u1ecdi n\u01a1i<span class=\"ez-toc-section-end\"><\/span><\/h3>\n<p>\u0110\u00e2y l\u00e0 l\u1ee3i \u00edch r\u00f5 r\u00e0ng v\u00e0 quan tr\u1ecdng nh\u1ea5t. H\u00e3y t\u01b0\u1edfng t\u01b0\u1ee3ng b\u1ea1n c\u1ea7n th\u1ef1c hi\u1ec7n m\u1ed9t ph\u00e9p t\u00ednh ph\u1ee9c t\u1ea1p ho\u1eb7c hi\u1ec3n th\u1ecb m\u1ed9t th\u00f4ng b\u00e1o theo \u0111\u1ecbnh d\u1ea1ng \u0111\u1eb7c bi\u1ec7t \u1edf nhi\u1ec1u n\u01a1i trong ch\u01b0\u01a1ng tr\u00ecnh. Thay v\u00ec sao ch\u00e9p v\u00e0 d\u00e1n (copy-paste) \u0111o\u1ea1n m\u00e3 \u0111\u00f3 nhi\u1ec1u l\u1ea7n, b\u1ea1n ch\u1ec9 c\u1ea7n vi\u1ebft n\u00f3 <strong>m\u1ed9t l\u1ea7n duy nh\u1ea5t<\/strong> b\u00ean trong m\u1ed9t h\u00e0m.<\/p>\n<p>Sau \u0111\u00f3, m\u1ed7i khi c\u1ea7n, b\u1ea1n ch\u1ec9 vi\u1ec7c <strong>g\u1ecdi h\u00e0m<\/strong> \u0111\u00f3. N\u1ebfu sau n\u00e0y b\u1ea1n c\u1ea7n thay \u0111\u1ed5i logic c\u1ee7a ph\u00e9p t\u00ednh hay \u0111\u1ecbnh d\u1ea1ng th\u00f4ng b\u00e1o, b\u1ea1n ch\u1ec9 c\u1ea7n s\u1eeda <strong>duy nh\u1ea5t<\/strong> \u1edf trong th\u00e2n h\u00e0m. M\u1ecdi n\u01a1i g\u1ecdi h\u00e0m \u0111\u00f3 s\u1ebd t\u1ef1 \u0111\u1ed9ng \u0111\u01b0\u1ee3c c\u1eadp nh\u1eadt theo logic m\u1edbi. \u0110i\u1ec1u n\u00e0y ti\u1ebft ki\u1ec7m c\u1ef1c k\u1ef3 nhi\u1ec1u th\u1eddi gian v\u00e0 c\u00f4ng s\u1ee9c.<\/p>\n<h3><span class=\"ez-toc-section\" id=\"Tang-tinh-Module-va-to-chuc-Code\"><\/span>T\u0103ng t\u00ednh Module v\u00e0 t\u1ed5 ch\u1ee9c Code<span class=\"ez-toc-section-end\"><\/span><\/h3>\n<p>H\u00e0m gi\u00fap b\u1ea1n <strong>chia nh\u1ecf (decompose)<\/strong> m\u1ed9t ch\u01b0\u01a1ng tr\u00ecnh l\u1edbn th\u00e0nh c\u00e1c <strong>module<\/strong> (kh\u1ed1i) ch\u1ee9c n\u0103ng nh\u1ecf h\u01a1n, \u0111\u1ed9c l\u1eadp h\u01a1n. M\u1ed7i h\u00e0m t\u1eadp trung gi\u1ea3i quy\u1ebft m\u1ed9t nhi\u1ec7m v\u1ee5 c\u1ee5 th\u1ec3. Gi\u1ed1ng nh\u01b0 vi\u1ec7c l\u1eafp r\u00e1p m\u1ed9t chi\u1ebfc xe t\u1eeb c\u00e1c b\u1ed9 ph\u1eadn ri\u00eang l\u1ebb (\u0111\u1ed9ng c\u01a1, b\u00e1nh xe, khung xe&#8230;), m\u1ed7i b\u1ed9 ph\u1eadn c\u00f3 ch\u1ee9c n\u0103ng ri\u00eang.<\/p>\n<p>C\u00e1ch ti\u1ebfp c\u1eadn module n\u00e0y l\u00e0m cho m\u00e3 ngu\u1ed3n c\u1ee7a b\u1ea1n tr\u1edf n\u00ean <strong>d\u1ec5 \u0111\u1ecdc, d\u1ec5 hi\u1ec3u v\u00e0 d\u1ec5 qu\u1ea3n l\u00fd<\/strong> h\u01a1n r\u1ea5t nhi\u1ec1u. Khi c\u1ea7n t\u00ecm hi\u1ec3u m\u1ed9t ch\u1ee9c n\u0103ng n\u00e0o \u0111\u00f3, b\u1ea1n ch\u1ec9 c\u1ea7n t\u1eadp trung v\u00e0o h\u00e0m t\u01b0\u01a1ng \u1ee9ng m\u00e0 kh\u00f4ng b\u1ecb ph\u00e2n t\u00e2m b\u1edfi c\u00e1c ph\u1ea7n kh\u00e1c c\u1ee7a ch\u01b0\u01a1ng tr\u00ecnh.<\/p>\n<h3><span class=\"ez-toc-section\" id=\"De-dang-bao-tri-va-sua-loi\"><\/span>D\u1ec5 d\u00e0ng b\u1ea3o tr\u00ec v\u00e0 s\u1eeda l\u1ed7i<span class=\"ez-toc-section-end\"><\/span><\/h3>\n<p>Khi m\u00e3 ngu\u1ed3n \u0111\u01b0\u1ee3c t\u1ed5 ch\u1ee9c th\u00e0nh c\u00e1c h\u00e0m r\u00f5 r\u00e0ng, vi\u1ec7c <strong>b\u1ea3o tr\u00ec (maintenance)<\/strong> v\u00e0 <strong>t\u00ecm l\u1ed7i (debugging)<\/strong> tr\u1edf n\u00ean \u0111\u01a1n gi\u1ea3n h\u01a1n \u0111\u00e1ng k\u1ec3. N\u1ebfu m\u1ed9t ch\u1ee9c n\u0103ng n\u00e0o \u0111\u00f3 ho\u1ea1t \u0111\u1ed9ng kh\u00f4ng \u0111\u00fang, b\u1ea1n c\u00f3 th\u1ec3 khoanh v\u00f9ng v\u1ea5n \u0111\u1ec1 n\u1eb1m \u1edf h\u00e0m n\u00e0o v\u00e0 ch\u1ec9 c\u1ea7n t\u1eadp trung s\u1eeda l\u1ed7i trong h\u00e0m \u0111\u00f3.<\/p>\n<p>Vi\u1ec7c s\u1eeda l\u1ed7i trong m\u1ed9t h\u00e0m \u0111\u1ed9c l\u1eadp \u00edt c\u00f3 kh\u1ea3 n\u0103ng g\u00e2y ra l\u1ed7i kh\u00f4ng mong mu\u1ed1n \u1edf c\u00e1c ph\u1ea7n kh\u00e1c c\u1ee7a ch\u01b0\u01a1ng tr\u00ecnh (\u00edt &#8220;side effect&#8221; h\u01a1n) so v\u1edbi vi\u1ec7c s\u1eeda m\u1ed9t \u0111o\u1ea1n code n\u1eb1m r\u1ea3i r\u00e1c kh\u1eafp n\u01a1i. \u0110i\u1ec1u n\u00e0y gi\u00fap gi\u1ea3m thi\u1ec3u r\u1ee7i ro v\u00e0 t\u0103ng t\u1ed1c \u0111\u1ed9 kh\u1eafc ph\u1ee5c s\u1ef1 c\u1ed1.<\/p>\n<h3><span class=\"ez-toc-section\" id=\"Truu-tuong-hoa-Abstraction-Che-giau-su-phuc-tap\"><\/span>Tr\u1eebu t\u01b0\u1ee3ng h\u00f3a (Abstraction): Che gi\u1ea5u s\u1ef1 ph\u1ee9c t\u1ea1p<span class=\"ez-toc-section-end\"><\/span><\/h3>\n<p>H\u00e0m cho ph\u00e9p ch\u00fang ta \u00e1p d\u1ee5ng nguy\u00ean t\u1eafc <strong>tr\u1eebu t\u01b0\u1ee3ng h\u00f3a (abstraction)<\/strong>. Ngh\u0129a l\u00e0, khi s\u1eed d\u1ee5ng m\u1ed9t h\u00e0m, b\u1ea1n ch\u1ec9 c\u1ea7n bi\u1ebft <strong>n\u00f3 l\u00e0m g\u00ec<\/strong> (ch\u1ee9c n\u0103ng), <strong>n\u00f3 c\u1ea7n g\u00ec<\/strong> (tham s\u1ed1 \u0111\u1ea7u v\u00e0o) v\u00e0 <strong>n\u00f3 tr\u1ea3 v\u1ec1 c\u00e1i g\u00ec<\/strong> (gi\u00e1 tr\u1ecb tr\u1ea3 v\u1ec1), m\u00e0 kh\u00f4ng c\u1ea7n quan t\u00e2m \u0111\u1ebfn vi\u1ec7c <strong>n\u00f3 th\u1ef1c hi\u1ec7n \u0111i\u1ec1u \u0111\u00f3 nh\u01b0 th\u1ebf n\u00e0o<\/strong> b\u00ean trong.<\/p>\n<p>V\u00ed d\u1ee5, khi b\u1ea1n s\u1eed d\u1ee5ng h\u00e0m <code>print()<\/code> trong Python \u0111\u1ec3 in m\u1ed9t c\u00e1i g\u00ec \u0111\u00f3 ra m\u00e0n h\u00ecnh, b\u1ea1n kh\u00f4ng c\u1ea7n bi\u1ebft chi ti\u1ebft c\u00e1ch Python t\u01b0\u01a1ng t\u00e1c v\u1edbi h\u1ec7 \u0111i\u1ec1u h\u00e0nh \u0111\u1ec3 hi\u1ec3n th\u1ecb ch\u1eef. B\u1ea1n ch\u1ec9 c\u1ea7n bi\u1ebft c\u00e1ch g\u1ecdi h\u00e0m <code>print(\"Hello\")<\/code> l\u00e0 \u0111\u1ee7. S\u1ef1 tr\u1eebu t\u01b0\u1ee3ng n\u00e0y gi\u00fap \u0111\u01a1n gi\u1ea3n h\u00f3a vi\u1ec7c s\u1eed d\u1ee5ng c\u00e1c ch\u1ee9c n\u0103ng ph\u1ee9c t\u1ea1p.<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/interdata.vn\/blog\/wp-content\/uploads\/2025\/04\/Function-ham-02.jpg\" alt=\"Function (h\u00e0m) 02\" width=\"750\" height=\"741\" class=\"aligncenter size-full wp-image-27451\" title=\"\" srcset=\"https:\/\/interdata.vn\/blog\/wp-content\/uploads\/2025\/04\/Function-ham-02.jpg 750w, https:\/\/interdata.vn\/blog\/wp-content\/uploads\/2025\/04\/Function-ham-02-300x296.jpg 300w, https:\/\/interdata.vn\/blog\/wp-content\/uploads\/2025\/04\/Function-ham-02-75x75.jpg 75w\" sizes=\"auto, (max-width: 750px) 100vw, 750px\" \/><\/p>\n<h2><span class=\"ez-toc-section\" id=\"Cau-truc-co-ban-cua-mot-Ham-Function-Structure\"><\/span>C\u1ea5u tr\u00fac c\u01a1 b\u1ea3n c\u1ee7a m\u1ed9t H\u00e0m (Function Structure)<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>M\u1eb7c d\u00f9 c\u00fa ph\u00e1p (syntax) c\u00f3 th\u1ec3 h\u01a1i kh\u00e1c nhau gi\u1eefa c\u00e1c ng\u00f4n ng\u1eef l\u1eadp tr\u00ecnh, h\u1ea7u h\u1ebft c\u00e1c h\u00e0m \u0111\u1ec1u c\u00f3 nh\u1eefng th\u00e0nh ph\u1ea7n c\u1ea5u tr\u00fac c\u01a1 b\u1ea3n gi\u1ed1ng nhau. Hi\u1ec3u r\u00f5 c\u1ea5u tr\u00fac n\u00e0y l\u00e0 b\u01b0\u1edbc \u0111\u1ea7u ti\u00ean \u0111\u1ec3 b\u1ea1n c\u00f3 th\u1ec3 t\u1ef1 vi\u1ebft v\u00e0 \u0111\u1ecdc hi\u1ec3u c\u00e1c h\u00e0m.<\/p>\n<p>H\u00e3y xem c\u1ea5u tr\u00fac t\u1ed5ng qu\u00e1t (d\u1ea1ng m\u00e3 gi\u1ea3 &#8211; pseudocode):<\/p>\n<p>\u0110o\u1ea1n m\u00e3<\/p>\n<pre><code class=\"language-plaintext\">[t\u1eeb_kh\u00f3a_\u0111\u1ecbnh_ngh\u0129a] ten_ham(tham_so_1, tham_so_2, ...) {\r\n  \/\/ Th\u00e2n h\u00e0m: Ch\u1ee9a c\u00e1c d\u00f2ng l\u1ec7nh th\u1ef1c thi nhi\u1ec7m v\u1ee5\r\n  \/\/ ... m\u00e3 l\u1ec7nh x\u1eed l\u00fd logic ...\r\n\r\n  [t\u1eeb_kh\u00f3a_tr\u1ea3_v\u1ec1] [gia_tri_tra_ve];\r\n}\r\n<\/code><\/pre>\n<p>B\u00e2y gi\u1edd, ch\u00fang ta s\u1ebd \u0111i s\u00e2u v\u00e0o t\u1eebng th\u00e0nh ph\u1ea7n:<\/p>\n<h3><span class=\"ez-toc-section\" id=\"Khai-bao-Dinh-nghia-Ham-Function-Declaration-Definition\"><\/span>Khai b\u00e1o \/ \u0110\u1ecbnh ngh\u0129a H\u00e0m (Function Declaration \/ Definition)<span class=\"ez-toc-section-end\"><\/span><\/h3>\n<p>\u0110\u00e2y l\u00e0 b\u01b0\u1edbc b\u1ea1n &#8220;t\u1ea1o ra&#8221; h\u00e0m. N\u00f3 th\u01b0\u1eddng b\u1eaft \u0111\u1ea7u b\u1eb1ng m\u1ed9t <strong>t\u1eeb kh\u00f3a (keyword)<\/strong> \u0111\u1eb7c bi\u1ec7t \u0111\u1ec3 b\u00e1o cho ng\u00f4n ng\u1eef l\u1eadp tr\u00ecnh bi\u1ebft b\u1ea1n \u0111ang \u0111\u1ecbnh ngh\u0129a m\u1ed9t h\u00e0m. V\u00ed d\u1ee5:<\/p>\n<ul>\n<li>Trong Python, b\u1ea1n d\u00f9ng t\u1eeb kh\u00f3a <code>def<\/code>.<\/li>\n<li>Trong JavaScript, C++, <a href=\"https:\/\/interdata.vn\/blog\/ngon-ngu-lap-trinh-java\/\">Java<\/a>, b\u1ea1n th\u01b0\u1eddng d\u00f9ng t\u1eeb kh\u00f3a <code>function<\/code> ho\u1eb7c ch\u1ec9 \u0111\u1ecbnh <a href=\"https:\/\/interdata.vn\/blog\/kieu-du-lieu-data-type\/\">ki\u1ec3u d\u1eef li\u1ec7u<\/a> tr\u1ea3 v\u1ec1.<\/li>\n<\/ul>\n<p>Sau t\u1eeb kh\u00f3a l\u00e0 \u0111\u1ebfn <strong>t\u00ean h\u00e0m<\/strong> v\u00e0 c\u1eb7p d\u1ea5u ngo\u1eb7c \u0111\u01a1n <code>()<\/code>. B\u00ean trong d\u1ea5u ngo\u1eb7c \u0111\u01a1n l\u00e0 danh s\u00e1ch c\u00e1c <strong>tham s\u1ed1<\/strong>, n\u1ebfu c\u00f3. Cu\u1ed1i c\u00f9ng l\u00e0 kh\u1ed1i l\u1ec7nh (th\u01b0\u1eddng n\u1eb1m trong d\u1ea5u ngo\u1eb7c nh\u1ecdn <code>{}<\/code> ho\u1eb7c th\u1ee5t l\u1ec1 \u0111\u1ea7u d\u00f2ng trong Python) ch\u1ee9a <strong>th\u00e2n h\u00e0m<\/strong>.<\/p>\n<h3><span class=\"ez-toc-section\" id=\"Ten-Ham-Function-Name-Cach-dat-ten-noi-len-tat-ca\"><\/span>T\u00ean H\u00e0m (Function Name): C\u00e1ch \u0111\u1eb7t t\u00ean n\u00f3i l\u00ean t\u1ea5t c\u1ea3<span class=\"ez-toc-section-end\"><\/span><\/h3>\n<p>T\u00ean h\u00e0m c\u1ef1c k\u1ef3 quan tr\u1ecdng! N\u00f3 gi\u1ed1ng nh\u01b0 t\u00ean c\u1ee7a c\u00f4ng th\u1ee9c n\u1ea5u \u0103n hay t\u00ean c\u1ee7a m\u1ed9t c\u00f4ng c\u1ee5. M\u1ed9t c\u00e1i t\u00ean t\u1ed1t ph\u1ea3i <strong>r\u00f5 r\u00e0ng, g\u1ee3i t\u1ea3<\/strong> \u0111\u01b0\u1ee3c ch\u1ee9c n\u0103ng m\u00e0 h\u00e0m \u0111\u00f3 th\u1ef1c hi\u1ec7n. Quy t\u1eafc ph\u1ed5 bi\u1ebfn l\u00e0 s\u1eed d\u1ee5ng <strong>\u0111\u1ed9ng t\u1eeb<\/strong> ho\u1eb7c c\u1ee5m \u0111\u1ed9ng t\u1eeb \u0111\u1ec3 \u0111\u1eb7t t\u00ean h\u00e0m.<\/p>\n<p>V\u00ed d\u1ee5: <code>tinhTong<\/code>, <code>kiemTraSoNguyenTo<\/code>, <code>inThongBaoLoi<\/code>, <code>getUserData<\/code>.<\/p>\n<p>Ngo\u00e0i ra, c\u00e1c ng\u00f4n ng\u1eef th\u01b0\u1eddng c\u00f3 quy \u01b0\u1edbc \u0111\u1eb7t t\u00ean ri\u00eang, v\u00ed d\u1ee5:<\/p>\n<ul>\n<li><strong>camelCase:<\/strong> <code>tinhTongHaiSo<\/code> (JavaScript, Java)<\/li>\n<li><strong>snake_case:<\/strong> <code>tinh_tong_hai_so<\/code> (Python)<\/li>\n<\/ul>\n<p>H\u00e3y tu\u00e2n th\u1ee7 quy \u01b0\u1edbc c\u1ee7a ng\u00f4n ng\u1eef b\u1ea1n \u0111ang d\u00f9ng \u0111\u1ec3 code d\u1ec5 \u0111\u1ecdc v\u00e0 nh\u1ea5t qu\u00e1n h\u01a1n. Tr\u00e1nh \u0111\u1eb7t t\u00ean h\u00e0m qu\u00e1 chung chung nh\u01b0 <code>xuLy<\/code>, <code>data<\/code>, <code>ham1<\/code>.<\/p>\n<h3><span class=\"ez-toc-section\" id=\"Tham-so-Parameters-%E2%80%9CNguyen-lieu%E2%80%9D-dau-vao-cua-Ham\"><\/span>Tham s\u1ed1 (Parameters): &#8220;Nguy\u00ean li\u1ec7u&#8221; \u0111\u1ea7u v\u00e0o c\u1ee7a H\u00e0m<span class=\"ez-toc-section-end\"><\/span><\/h3>\n<p><strong>Tham s\u1ed1 (parameter)<\/strong> l\u00e0 c\u00e1c <strong>bi\u1ebfn<\/strong> \u0111\u01b0\u1ee3c khai b\u00e1o b\u00ean trong c\u1eb7p d\u1ea5u ngo\u1eb7c \u0111\u01a1n <code>()<\/code> c\u1ee7a ph\u1ea7n \u0111\u1ecbnh ngh\u0129a h\u00e0m. Ch\u00fang ho\u1ea1t \u0111\u1ed9ng nh\u01b0 nh\u1eefng &#8220;bi\u1ebfn gi\u1eef ch\u1ed7&#8221; (placeholders) \u0111\u1ec3 nh\u1eadn d\u1eef li\u1ec7u \u0111\u1ea7u v\u00e0o m\u00e0 h\u00e0m c\u1ea7n \u0111\u1ec3 th\u1ef1c hi\u1ec7n c\u00f4ng vi\u1ec7c c\u1ee7a n\u00f3.<\/p>\n<p>V\u00ed d\u1ee5, h\u00e0m <code>tinhTong(soA, soB)<\/code> c\u00f3 hai tham s\u1ed1 l\u00e0 <code>soA<\/code> v\u00e0 <code>soB<\/code>. Khi h\u00e0m n\u00e0y \u0111\u01b0\u1ee3c g\u1ecdi, n\u00f3 s\u1ebd c\u1ea7n nh\u1eadn hai gi\u00e1 tr\u1ecb c\u1ee5 th\u1ec3 \u0111\u1ec3 g\u00e1n cho <code>soA<\/code> v\u00e0 <code>soB<\/code> tr\u01b0\u1edbc khi th\u1ef1c hi\u1ec7n ph\u00e9p c\u1ed9ng. M\u1ed9t h\u00e0m c\u00f3 th\u1ec3 kh\u00f4ng c\u00f3 tham s\u1ed1 n\u00e0o, c\u00f3 m\u1ed9t ho\u1eb7c nhi\u1ec1u tham s\u1ed1.<\/p>\n<p>Trong m\u1ed9t s\u1ed1 ng\u00f4n ng\u1eef l\u1eadp tr\u00ecnh (nh\u01b0 C++, Java), b\u1ea1n c\u1ea7n ch\u1ec9 \u0111\u1ecbnh <strong>ki\u1ec3u d\u1eef li\u1ec7u (data type)<\/strong> cho t\u1eebng tham s\u1ed1 (v\u00ed d\u1ee5: <code>int soA<\/code>, <code>string ten<\/code>). Trong c\u00e1c ng\u00f4n ng\u1eef kh\u00e1c (nh\u01b0 Python, JavaScript), b\u1ea1n th\u01b0\u1eddng kh\u00f4ng c\u1ea7n l\u00e0m \u0111i\u1ec1u n\u00e0y khi khai b\u00e1o.<\/p>\n<h3><span class=\"ez-toc-section\" id=\"Doi-so-Arguments-Gia-tri-thuc-te-truyen-vao-Ham\"><\/span>\u0110\u1ed1i s\u1ed1 (Arguments): Gi\u00e1 tr\u1ecb th\u1ef1c t\u1ebf truy\u1ec1n v\u00e0o H\u00e0m<span class=\"ez-toc-section-end\"><\/span><\/h3>\n<p>Khi b\u1ea1n <strong>g\u1ecdi (call)<\/strong> m\u1ed9t h\u00e0m, c\u00e1c gi\u00e1 tr\u1ecb <strong>c\u1ee5 th\u1ec3<\/strong> m\u00e0 b\u1ea1n truy\u1ec1n v\u00e0o cho c\u00e1c tham s\u1ed1 \u0111\u01b0\u1ee3c g\u1ecdi l\u00e0 <strong>\u0111\u1ed1i s\u1ed1 (argument)<\/strong>. H\u00e3y ph\u00e2n bi\u1ec7t r\u00f5 r\u00e0ng: <strong>tham s\u1ed1<\/strong> l\u00e0 t\u00ean bi\u1ebfn trong \u0111\u1ecbnh ngh\u0129a h\u00e0m, c\u00f2n <strong>\u0111\u1ed1i s\u1ed1<\/strong> l\u00e0 gi\u00e1 tr\u1ecb th\u1ef1c t\u1ebf \u0111\u01b0\u1ee3c truy\u1ec1n v\u00e0o khi h\u00e0m \u0111\u01b0\u1ee3c g\u1ecdi.<\/p>\n<p>V\u00ed d\u1ee5: V\u1edbi h\u00e0m <code>tinhTong(soA, soB)<\/code>, khi b\u1ea1n g\u1ecdi <code>ketQua = tinhTong(5, 10)<\/code>, th\u00ec:<\/p>\n<ul>\n<li><code>soA<\/code> v\u00e0 <code>soB<\/code> l\u00e0 c\u00e1c <strong>tham s\u1ed1<\/strong>.<\/li>\n<li><code>5<\/code> v\u00e0 <code>10<\/code> l\u00e0 c\u00e1c <strong>\u0111\u1ed1i s\u1ed1<\/strong>. Gi\u00e1 tr\u1ecb <code>5<\/code> s\u1ebd \u0111\u01b0\u1ee3c g\u00e1n cho <code>soA<\/code>, v\u00e0 <code>10<\/code> s\u1ebd \u0111\u01b0\u1ee3c g\u00e1n cho <code>soB<\/code> b\u00ean trong h\u00e0m <code>tinhTong<\/code> khi n\u00f3 th\u1ef1c thi.<\/li>\n<\/ul>\n<p>S\u1ed1 l\u01b0\u1ee3ng v\u00e0 th\u1ee9 t\u1ef1 c\u00e1c \u0111\u1ed1i s\u1ed1 th\u01b0\u1eddng ph\u1ea3i kh\u1edbp v\u1edbi s\u1ed1 l\u01b0\u1ee3ng v\u00e0 th\u1ee9 t\u1ef1 c\u00e1c tham s\u1ed1 \u0111\u00e3 \u0111\u1ecbnh ngh\u0129a (tr\u1eeb m\u1ed9t s\u1ed1 tr\u01b0\u1eddng h\u1ee3p \u0111\u1eb7c bi\u1ec7t nh\u01b0 tham s\u1ed1 m\u1eb7c \u0111\u1ecbnh, \u0111\u1ed1i s\u1ed1 t\u00f9y ch\u1ecdn&#8230;).<\/p>\n<h3><span class=\"ez-toc-section\" id=\"Than-Ham-Function-Body-%E2%80%9CNha-may%E2%80%9D-xu-ly-logic\"><\/span>Th\u00e2n H\u00e0m (Function Body): &#8220;Nh\u00e0 m\u00e1y&#8221; x\u1eed l\u00fd logic<span class=\"ez-toc-section-end\"><\/span><\/h3>\n<p>\u0110\u00e2y l\u00e0 ph\u1ea7n quan tr\u1ecdng nh\u1ea5t, ch\u1ee9a <strong>to\u00e0n b\u1ed9 c\u00e1c d\u00f2ng l\u1ec7nh (code)<\/strong> th\u1ef1c hi\u1ec7n nhi\u1ec7m v\u1ee5 c\u1ee5 th\u1ec3 c\u1ee7a h\u00e0m. Th\u00e2n h\u00e0m n\u1eb1m b\u00ean trong kh\u1ed1i l\u1ec7nh (th\u01b0\u1eddng l\u00e0 <code>{}<\/code> ho\u1eb7c kh\u1ed1i th\u1ee5t l\u1ec1). Logic x\u1eed l\u00fd c\u00f3 th\u1ec3 \u0111\u01a1n gi\u1ea3n ch\u1ec9 v\u00e0i d\u00f2ng ho\u1eb7c r\u1ea5t ph\u1ee9c t\u1ea1p t\u00f9y thu\u1ed9c v\u00e0o c\u00f4ng vi\u1ec7c h\u00e0m \u0111\u1ea3m nhi\u1ec7m.<\/p>\n<p>B\u00ean trong th\u00e2n h\u00e0m, b\u1ea1n c\u00f3 th\u1ec3 khai b\u00e1o c\u00e1c bi\u1ebfn c\u1ee5c b\u1ed9 (ch\u1ec9 t\u1ed3n t\u1ea1i b\u00ean trong h\u00e0m), s\u1eed d\u1ee5ng c\u00e1c tham s\u1ed1 \u0111\u1ea7u v\u00e0o, th\u1ef1c hi\u1ec7n c\u00e1c ph\u00e9p t\u00ednh, g\u1ecdi c\u00e1c h\u00e0m kh\u00e1c, v\u00e0 cu\u1ed1i c\u00f9ng l\u00e0 chu\u1ea9n b\u1ecb k\u1ebft qu\u1ea3 (n\u1ebfu c\u1ea7n tr\u1ea3 v\u1ec1).<\/p>\n<h3><span class=\"ez-toc-section\" id=\"Gia-tri-tra-ve-Return-Value-Ket-qua-Ham-tao-ra\"><\/span>Gi\u00e1 tr\u1ecb tr\u1ea3 v\u1ec1 (Return Value): K\u1ebft qu\u1ea3 H\u00e0m t\u1ea1o ra<span class=\"ez-toc-section-end\"><\/span><\/h3>\n<p>Sau khi ho\u00e0n th\u00e0nh c\u00f4ng vi\u1ec7c, m\u1ed9t h\u00e0m c\u00f3 th\u1ec3 (nh\u01b0ng kh\u00f4ng b\u1eaft bu\u1ed9c) <strong>tr\u1ea3 v\u1ec1 (return)<\/strong> m\u1ed9t gi\u00e1 tr\u1ecb k\u1ebft qu\u1ea3 cho n\u01a1i \u0111\u00e3 g\u1ecdi n\u00f3. T\u1eeb kh\u00f3a <code>return<\/code> th\u01b0\u1eddng \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng cho m\u1ee5c \u0111\u00edch n\u00e0y, theo sau l\u00e0 gi\u00e1 tr\u1ecb ho\u1eb7c bi\u1ebfn ch\u1ee9a k\u1ebft qu\u1ea3 c\u1ea7n tr\u1ea3 v\u1ec1.<\/p>\n<p>V\u00ed d\u1ee5: H\u00e0m <code>tinhTong(soA, soB)<\/code> s\u1ebd c\u00f3 l\u1ec7nh <code>return soA + soB;<\/code> trong th\u00e2n h\u00e0m \u0111\u1ec3 tr\u1ea3 v\u1ec1 t\u1ed5ng c\u1ee7a hai s\u1ed1. N\u01a1i g\u1ecdi h\u00e0m c\u00f3 th\u1ec3 nh\u1eadn gi\u00e1 tr\u1ecb n\u00e0y v\u00e0 s\u1eed d\u1ee5ng n\u00f3, v\u00ed d\u1ee5: <code>ketQua = tinhTong(5, 10);<\/code> \/\/ <code>ketQua<\/code> s\u1ebd nh\u1eadn gi\u00e1 tr\u1ecb 8.<\/p>\n<p>N\u1ebfu m\u1ed9t h\u00e0m kh\u00f4ng c\u1ea7n tr\u1ea3 v\u1ec1 k\u1ebft qu\u1ea3 n\u00e0o (v\u00ed d\u1ee5: h\u00e0m ch\u1ec9 \u0111\u1ec3 in m\u1ed9t th\u00f4ng b\u00e1o ra m\u00e0n h\u00ecnh), n\u00f3 c\u00f3 th\u1ec3 kh\u00f4ng c\u00f3 l\u1ec7nh <code>return<\/code>, ho\u1eb7c c\u00f3 l\u1ec7nh <code>return;<\/code> m\u00e0 kh\u00f4ng k\u00e8m gi\u00e1 tr\u1ecb n\u00e0o. Trong nhi\u1ec1u ng\u00f4n ng\u1eef, nh\u1eefng h\u00e0m nh\u01b0 v\u1eady \u0111\u01b0\u1ee3c g\u1ecdi l\u00e0 h\u00e0m <code>void<\/code> ho\u1eb7c c\u00f3 ki\u1ec3u tr\u1ea3 v\u1ec1 l\u00e0 <code>void<\/code>.<\/p>\n<h2><span class=\"ez-toc-section\" id=\"Cach-khai-bao-va-goi-Ham-Vi-du-thuc-te\"><\/span>C\u00e1ch khai b\u00e1o v\u00e0 g\u1ecdi H\u00e0m: V\u00ed d\u1ee5 th\u1ef1c t\u1ebf<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>L\u00fd thuy\u1ebft l\u00e0 v\u1eady, nh\u01b0ng c\u00e1ch t\u1ed1t nh\u1ea5t \u0111\u1ec3 hi\u1ec3u h\u00e0m l\u00e0 xem qua c\u00e1c v\u00ed d\u1ee5 c\u1ee5 th\u1ec3. Ch\u00fang ta s\u1ebd xem c\u00e1ch khai b\u00e1o v\u00e0 g\u1ecdi m\u1ed9t h\u00e0m \u0111\u01a1n gi\u1ea3n b\u1eb1ng m\u00e3 gi\u1ea3 (pseudocode), sau \u0111\u00f3 l\u00e0 v\u00ed d\u1ee5 trong hai ng\u00f4n ng\u1eef ph\u1ed5 bi\u1ebfn: Python v\u00e0 JavaScript.<\/p>\n<p><strong>Nhi\u1ec7m v\u1ee5:<\/strong> Vi\u1ebft m\u1ed9t h\u00e0m nh\u1eadn v\u00e0o t\u00ean c\u1ee7a m\u1ed9t ng\u01b0\u1eddi v\u00e0 tr\u1ea3 v\u1ec1 l\u1eddi ch\u00e0o &#8220;Xin ch\u00e0o, [t\u00ean ng\u01b0\u1eddi \u0111\u00f3]!&#8221;.<\/p>\n<h3><span class=\"ez-toc-section\" id=\"Vi-du-Khai-bao-Ham-don-gian\"><\/span>V\u00ed d\u1ee5 Khai b\u00e1o H\u00e0m \u0111\u01a1n gi\u1ea3n<span class=\"ez-toc-section-end\"><\/span><\/h3>\n<p><strong>1. M\u00e3 gi\u1ea3 (Pseudocode):<\/strong><\/p>\n<p>\u0110o\u1ea1n m\u00e3<\/p>\n<pre><code class=\"language-plaintext\">FUNCTION taoLoiChao(ten) {\r\n  loiChaoHoanChinh = \"Xin ch\u00e0o, \" + ten + \"!\";\r\n  RETURN loiChaoHoanChinh;\r\n}\r\n<\/code><\/pre>\n<ul>\n<li><code>FUNCTION<\/code>: T\u1eeb kh\u00f3a b\u00e1o hi\u1ec7u \u0111\u1ecbnh ngh\u0129a h\u00e0m.<\/li>\n<li><code>taoLoiChao<\/code>: T\u00ean h\u00e0m ch\u00fang ta \u0111\u1eb7t.<\/li>\n<li><code>(ten)<\/code>: H\u00e0m n\u00e0y c\u00f3 m\u1ed9t tham s\u1ed1 t\u00ean l\u00e0 <code>ten<\/code>.<\/li>\n<li><code>{ ... }<\/code>: Th\u00e2n h\u00e0m.<\/li>\n<li><code>loiChaoHoanChinh = ...<\/code>: T\u1ea1o ra chu\u1ed7i l\u1eddi ch\u00e0o.<\/li>\n<li><code>RETURN<\/code>: T\u1eeb kh\u00f3a tr\u1ea3 v\u1ec1 k\u1ebft qu\u1ea3.<\/li>\n<\/ul>\n<p><strong>2. Python:<\/strong><\/p>\n<p>Python<\/p>\n<pre><code class=\"language-plaintext\">def tao_loi_chao(ten):\r\n  \"\"\"H\u00e0m n\u00e0y nh\u1eadn v\u00e0o t\u00ean v\u00e0 tr\u1ea3 v\u1ec1 l\u1eddi ch\u00e0o.\"\"\"\r\n  loi_chao_hoan_chinh = \"Xin ch\u00e0o, \" + ten + \"!\"\r\n  return loi_chao_hoan_chinh\r\n\r\n# Gi\u1ea3i th\u00edch:\r\n# - def: T\u1eeb kh\u00f3a \u0111\u1ecbnh ngh\u0129a h\u00e0m trong Python.\r\n# - tao_loi_chao: T\u00ean h\u00e0m (theo quy \u01b0\u1edbc snake_case).\r\n# - (ten): Tham s\u1ed1 \u0111\u1ea7u v\u00e0o.\r\n# - \"\"\"...\"\"\": Docstring - ph\u1ea7n m\u00f4 t\u1ea3 h\u00e0m (r\u1ea5t n\u00ean c\u00f3).\r\n# - Th\u00e2n h\u00e0m \u0111\u01b0\u1ee3c th\u1ee5t l\u1ec1 v\u00e0o trong.\r\n# - return: Tr\u1ea3 v\u1ec1 gi\u00e1 tr\u1ecb \u0111\u00e3 t\u1ea1o.\r\n<\/code><\/pre>\n<p><strong>3. JavaScript:<\/strong><\/p>\n<p>JavaScript<\/p>\n<pre><code class=\"language-plaintext\">function taoLoiChao(ten) {\r\n  \/\/ H\u00e0m n\u00e0y nh\u1eadn v\u00e0o t\u00ean v\u00e0 tr\u1ea3 v\u1ec1 l\u1eddi ch\u00e0o.\r\n  const loiChaoHoanChinh = \"Xin ch\u00e0o, \" + ten + \"!\";\r\n  return loiChaoHoanChinh;\r\n}\r\n\r\n\/\/ Gi\u1ea3i th\u00edch:\r\n\/\/ - function: T\u1eeb kh\u00f3a \u0111\u1ecbnh ngh\u0129a h\u00e0m trong JavaScript.\r\n\/\/ - taoLoiChao: T\u00ean h\u00e0m (theo quy \u01b0\u1edbc camelCase).\r\n\/\/ - (ten): Tham s\u1ed1 \u0111\u1ea7u v\u00e0o.\r\n\/\/ - \/\/ ... : Ch\u00fa th\u00edch m\u00f4 t\u1ea3 h\u00e0m.\r\n\/\/ - { ... }: Kh\u1ed1i l\u1ec7nh ch\u1ee9a th\u00e2n h\u00e0m.\r\n\/\/ - const: Khai b\u00e1o bi\u1ebfn ch\u1ee9a l\u1eddi ch\u00e0o.\r\n\/\/ - return: Tr\u1ea3 v\u1ec1 gi\u00e1 tr\u1ecb.\r\n<\/code><\/pre>\n<h3><span class=\"ez-toc-section\" id=\"Vi-du-Goi-Ham-tuong-ung\"><\/span>V\u00ed d\u1ee5 G\u1ecdi H\u00e0m t\u01b0\u01a1ng \u1ee9ng<span class=\"ez-toc-section-end\"><\/span><\/h3>\n<p>Sau khi \u0111\u00e3 \u0111\u1ecbnh ngh\u0129a h\u00e0m <code>taoLoiChao<\/code>, ch\u00fang ta c\u00f3 th\u1ec3 g\u1ecdi n\u00f3 \u0111\u1ec3 s\u1eed d\u1ee5ng:<\/p>\n<p><strong>1. M\u00e3 gi\u1ea3:<\/strong><\/p>\n<p>\u0110o\u1ea1n m\u00e3<\/p>\n<pre><code class=\"language-plaintext\">loiChaoCuaAn = taoLoiChao(\"An\");\r\nPRINT loiChaoCuaAn; \/\/ K\u1ebft qu\u1ea3 s\u1ebd in ra: Xin ch\u00e0o, An!\r\n\r\nloiChaoCuaBinh = taoLoiChao(\"B\u00ecnh\");\r\nPRINT loiChaoCuaBinh; \/\/ K\u1ebft qu\u1ea3 s\u1ebd in ra: Xin ch\u00e0o, B\u00ecnh!\r\n<\/code><\/pre>\n<p><strong>2. Python:<\/strong><\/p>\n<p>Python<\/p>\n<pre><code class=\"language-plaintext\">loi_chao_cua_an = tao_loi_chao(\"An\")\r\nprint(loi_chao_cua_an) # Output: Xin ch\u00e0o, An!\r\n\r\nloi_chao_cua_binh = tao_loi_chao(\"B\u00ecnh\")\r\nprint(loi_chao_cua_binh) # Output: Xin ch\u00e0o, B\u00ecnh!\r\n\r\n# B\u1ea1n c\u0169ng c\u00f3 th\u1ec3 g\u1ecdi v\u00e0 in tr\u1ef1c ti\u1ebfp\r\nprint(tao_loi_chao(\"Lan\")) # Output: Xin ch\u00e0o, Lan!\r\n<\/code><\/pre>\n<p><strong>3. JavaScript:<\/strong><\/p>\n<p>JavaScript<\/p>\n<pre><code class=\"language-plaintext\">let loiChaoCuaAn = taoLoiChao(\"An\");\r\nconsole.log(loiChaoCuaAn); \/\/ Output: Xin ch\u00e0o, An!\r\n\r\nlet loiChaoCuaBinh = taoLoiChao(\"B\u00ecnh\");\r\nconsole.log(loiChaoCuaBinh); \/\/ Output: Xin ch\u00e0o, B\u00ecnh!\r\n\r\n\/\/ G\u1ecdi v\u00e0 log tr\u1ef1c ti\u1ebfp\r\nconsole.log(taoLoiChao(\"Lan\")); \/\/ Output: Xin ch\u00e0o, Lan!\r\n<\/code><\/pre>\n<p>Nh\u01b0 b\u1ea1n th\u1ea5y, ch\u00fang ta ch\u1ec9 c\u1ea7n \u0111\u1ecbnh ngh\u0129a h\u00e0m <code>taoLoiChao<\/code> m\u1ed9t l\u1ea7n, sau \u0111\u00f3 c\u00f3 th\u1ec3 g\u1ecdi n\u00f3 bao nhi\u00eau l\u1ea7n t\u00f9y th\u00edch v\u1edbi c\u00e1c <strong>\u0111\u1ed1i s\u1ed1<\/strong> (t\u00ean) kh\u00e1c nhau \u0111\u1ec3 t\u1ea1o ra nh\u1eefng l\u1eddi ch\u00e0o t\u01b0\u01a1ng \u1ee9ng. \u0110\u00e2y ch\u00ednh l\u00e0 s\u1ee9c m\u1ea1nh c\u1ee7a vi\u1ec7c <strong>t\u00e1i s\u1eed d\u1ee5ng code<\/strong>!<\/p>\n<h2><span class=\"ez-toc-section\" id=\"Phan-loai-Ham-co-ban-thuong-gap\"><\/span>Ph\u00e2n lo\u1ea1i H\u00e0m c\u01a1 b\u1ea3n th\u01b0\u1eddng g\u1eb7p<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>Trong qu\u00e1 tr\u00ecnh h\u1ecdc l\u1eadp tr\u00ecnh, b\u1ea1n s\u1ebd g\u1eb7p nhi\u1ec1u lo\u1ea1i h\u00e0m kh\u00e1c nhau. D\u01b0\u1edbi \u0111\u00e2y l\u00e0 m\u1ed9t v\u00e0i c\u00e1ch ph\u00e2n lo\u1ea1i c\u01a1 b\u1ea3n gi\u00fap b\u1ea1n h\u00ecnh dung r\u00f5 h\u01a1n:<\/p>\n<ol>\n<li><strong>H\u00e0m do ng\u01b0\u1eddi d\u00f9ng \u0111\u1ecbnh ngh\u0129a (User-Defined Functions):<\/strong> \u0110\u00e2y l\u00e0 nh\u1eefng h\u00e0m do ch\u00ednh b\u1ea1n (l\u1eadp tr\u00ecnh vi\u00ean) t\u1ea1o ra \u0111\u1ec3 th\u1ef1c hi\u1ec7n c\u00e1c t\u00e1c v\u1ee5 c\u1ee5 th\u1ec3 cho ch\u01b0\u01a1ng tr\u00ecnh c\u1ee7a m\u00ecnh, gi\u1ed1ng nh\u01b0 h\u00e0m <code>taoLoiChao<\/code> ch\u00fang ta v\u1eeba vi\u1ebft. B\u1ea1n to\u00e0n quy\u1ec1n ki\u1ec3m so\u00e1t t\u00ean, tham s\u1ed1, v\u00e0 logic x\u1eed l\u00fd c\u1ee7a ch\u00fang.<\/li>\n<li><strong>H\u00e0m d\u1ef1ng s\u1eb5n (Built-in Functions):<\/strong> H\u1ea7u h\u1ebft c\u00e1c ng\u00f4n ng\u1eef l\u1eadp tr\u00ecnh \u0111\u1ec1u cung c\u1ea5p s\u1eb5n m\u1ed9t b\u1ed9 c\u00e1c h\u00e0m th\u00f4ng d\u1ee5ng \u0111\u1ec3 b\u1ea1n s\u1eed d\u1ee5ng ngay m\u00e0 kh\u00f4ng c\u1ea7n \u0111\u1ecbnh ngh\u0129a l\u1ea1i. V\u00ed d\u1ee5:\n<ul>\n<li>H\u00e0m <code>print()<\/code> trong Python \u0111\u1ec3 in d\u1eef li\u1ec7u ra m\u00e0n h\u00ecnh.<\/li>\n<li>H\u00e0m <code>len()<\/code> trong Python \u0111\u1ec3 l\u1ea5y \u0111\u1ed9 d\u00e0i (s\u1ed1 ph\u1ea7n t\u1eed) c\u1ee7a m\u1ed9t chu\u1ed7i, danh s\u00e1ch&#8230;<\/li>\n<li>H\u00e0m <code>console.log()<\/code> trong JavaScript \u0111\u1ec3 in th\u00f4ng tin ra b\u1ea3ng \u0111i\u1ec1u khi\u1ec3n c\u1ee7a tr\u00ecnh duy\u1ec7t.<\/li>\n<li>C\u00e1c h\u00e0m to\u00e1n h\u1ecdc nh\u01b0 <code>Math.sqrt()<\/code> (t\u00ednh c\u0103n b\u1eadc hai) trong JavaScript. Vi\u1ec7c s\u1eed d\u1ee5ng hi\u1ec7u qu\u1ea3 c\u00e1c h\u00e0m d\u1ef1ng s\u1eb5n gi\u00fap b\u1ea1n ti\u1ebft ki\u1ec7m th\u1eddi gian v\u00e0 vi\u1ebft code ng\u1eafn g\u1ecdn h\u01a1n.<\/li>\n<\/ul>\n<\/li>\n<li><strong>H\u00e0m c\u00f3 gi\u00e1 tr\u1ecb tr\u1ea3 v\u1ec1 v\u00e0 H\u00e0m kh\u00f4ng c\u00f3 gi\u00e1 tr\u1ecb tr\u1ea3 v\u1ec1 (Void Functions):<\/strong>\n<ul>\n<li>Nh\u01b0 \u0111\u00e3 \u0111\u1ec1 c\u1eadp, h\u00e0m c\u00f3 th\u1ec3 d\u00f9ng <code>return<\/code> \u0111\u1ec3 tr\u1ea3 v\u1ec1 m\u1ed9t k\u1ebft qu\u1ea3 (v\u00ed d\u1ee5: <code>taoLoiChao<\/code>, c\u00e1c h\u00e0m t\u00ednh to\u00e1n).<\/li>\n<li>M\u1ed9t s\u1ed1 h\u00e0m ch\u1ec9 th\u1ef1c hi\u1ec7n m\u1ed9t h\u00e0nh \u0111\u1ed9ng n\u00e0o \u0111\u00f3 m\u00e0 kh\u00f4ng c\u1ea7n tr\u1ea3 v\u1ec1 k\u1ebft qu\u1ea3 (v\u00ed d\u1ee5: h\u00e0m ch\u1ec9 \u0111\u1ec3 in th\u00f4ng tin, h\u00e0m thay \u0111\u1ed5i tr\u1ea1ng th\u00e1i c\u1ee7a m\u1ed9t \u0111\u1ed1i t\u01b0\u1ee3ng). Nh\u1eefng h\u00e0m n\u00e0y th\u01b0\u1eddng \u0111\u01b0\u1ee3c g\u1ecdi l\u00e0 h\u00e0m <code>void<\/code>.<\/li>\n<\/ul>\n<\/li>\n<li><strong>H\u00e0m c\u00f3 tham s\u1ed1 v\u00e0 H\u00e0m kh\u00f4ng c\u00f3 tham s\u1ed1:<\/strong>\n<ul>\n<li>H\u00e0m <code>taoLoiChao(ten)<\/code> l\u00e0 h\u00e0m c\u00f3 tham s\u1ed1 (<code>ten<\/code>).<\/li>\n<li>B\u1ea1n c\u0169ng c\u00f3 th\u1ec3 vi\u1ebft h\u00e0m kh\u00f4ng c\u1ea7n d\u1eef li\u1ec7u \u0111\u1ea7u v\u00e0o, v\u00ed d\u1ee5 h\u00e0m <code>layThoiGianHienTai()<\/code> kh\u00f4ng c\u1ea7n tham s\u1ed1 m\u00e0 v\u1eabn tr\u1ea3 v\u1ec1 th\u1eddi gian hi\u1ec7n t\u1ea1i.<\/li>\n<\/ul>\n<\/li>\n<\/ol>\n<p>Ngo\u00e0i ra, khi t\u00ecm hi\u1ec3u s\u00e2u h\u01a1n, b\u1ea1n s\u1ebd g\u1eb7p c\u00e1c kh\u00e1i ni\u1ec7m n\u00e2ng cao h\u01a1n nh\u01b0 h\u00e0m \u1ea9n danh (anonymous functions &#8211; lambda trong Python, arrow functions trong JS), h\u00e0m \u0111\u1ec7 quy (recursive functions), ph\u01b0\u01a1ng th\u1ee9c (methods &#8211; h\u00e0m thu\u1ed9c v\u1ec1 \u0111\u1ed1i t\u01b0\u1ee3ng trong l\u1eadp tr\u00ecnh h\u01b0\u1edbng \u0111\u1ed1i t\u01b0\u1ee3ng)&#8230; nh\u01b0ng nh\u1eefng lo\u1ea1i c\u01a1 b\u1ea3n tr\u00ean l\u00e0 \u0111\u1ee7 \u0111\u1ec3 b\u1ea1n b\u1eaft \u0111\u1ea7u.<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/interdata.vn\/blog\/wp-content\/uploads\/2025\/04\/Function-ham-03.jpg\" alt=\"Function (h\u00e0m) 03\" width=\"750\" height=\"437\" class=\"aligncenter size-full wp-image-27452\" title=\"\" srcset=\"https:\/\/interdata.vn\/blog\/wp-content\/uploads\/2025\/04\/Function-ham-03.jpg 750w, https:\/\/interdata.vn\/blog\/wp-content\/uploads\/2025\/04\/Function-ham-03-300x175.jpg 300w\" sizes=\"auto, (max-width: 750px) 100vw, 750px\" \/><\/p>\n<h2><span class=\"ez-toc-section\" id=\"Meo-su-dung-Ham-hieu-qua-cho-nguoi-moi-bat-dau\"><\/span>M\u1eb9o s\u1eed d\u1ee5ng H\u00e0m hi\u1ec7u qu\u1ea3 cho ng\u01b0\u1eddi m\u1edbi b\u1eaft \u0111\u1ea7u<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>Vi\u1ebft h\u00e0m kh\u00f4ng ch\u1ec9 \u0111\u01a1n gi\u1ea3n l\u00e0 t\u1ea1o ra c\u00e1c kh\u1ed1i code, m\u00e0 c\u00f2n l\u00e0 ngh\u1ec7 thu\u1eadt t\u1ed5 ch\u1ee9c v\u00e0 l\u00e0m cho m\u00e3 ngu\u1ed3n tr\u1edf n\u00ean t\u1ed1t h\u01a1n. D\u01b0\u1edbi \u0111\u00e2y l\u00e0 m\u1ed9t v\u00e0i m\u1eb9o h\u1eefu \u00edch khi b\u1ea1n b\u1eaft \u0111\u1ea7u l\u00e0m vi\u1ec7c v\u1edbi h\u00e0m:<\/p>\n<ol>\n<li><strong>\u0110\u1eb7t t\u00ean H\u00e0m r\u00f5 r\u00e0ng, c\u00f3 \u00fd ngh\u0129a:<\/strong> Nh\u01b0 \u0111\u00e3 n\u00f3i, t\u00ean h\u00e0m n\u00ean th\u1ec3 hi\u1ec7n r\u00f5 ch\u1ee9c n\u0103ng n\u00f3 th\u1ef1c hi\u1ec7n. D\u00f9ng \u0111\u1ed9ng t\u1eeb v\u00e0 tu\u00e2n th\u1ee7 quy \u01b0\u1edbc \u0111\u1eb7t t\u00ean (camelCase\/snake_case). T\u00ean h\u00e0m t\u1ed1t gi\u00fap ng\u01b0\u1eddi kh\u00e1c (v\u00e0 ch\u00ednh b\u1ea1n sau n\u00e0y) \u0111\u1ecdc code d\u1ec5 d\u00e0ng h\u01a1n.<\/li>\n<li><strong>M\u1ed7i H\u00e0m n\u00ean l\u00e0m m\u1ed9t vi\u1ec7c duy nh\u1ea5t (Single Responsibility Principle):<\/strong> C\u1ed1 g\u1eafng gi\u1eef cho m\u1ed7i h\u00e0m ch\u1ec9 t\u1eadp trung th\u1ef1c hi\u1ec7n <strong>m\u1ed9t<\/strong> nhi\u1ec7m v\u1ee5 c\u1ee5 th\u1ec3 v\u00e0 l\u00e0m t\u1ed1t nhi\u1ec7m v\u1ee5 \u0111\u00f3. \u0110\u1eebng c\u1ed1 nh\u1ed3i nh\u00e9t qu\u00e1 nhi\u1ec1u logic kh\u00e1c nhau v\u00e0o c\u00f9ng m\u1ed9t h\u00e0m. H\u00e0m qu\u00e1 d\u00e0i v\u00e0 l\u00e0m nhi\u1ec1u vi\u1ec7c s\u1ebd kh\u00f3 hi\u1ec3u, kh\u00f3 ki\u1ec3m th\u1eed v\u00e0 kh\u00f3 b\u1ea3o tr\u00ec.<\/li>\n<li><strong>Gi\u1eef H\u00e0m ng\u1eafn g\u1ecdn:<\/strong> M\u1ed9t h\u00e0m ng\u1eafn th\u01b0\u1eddng d\u1ec5 \u0111\u1ecdc v\u00e0 d\u1ec5 hi\u1ec3u h\u01a1n. N\u1ebfu h\u00e0m c\u1ee7a b\u1ea1n tr\u1edf n\u00ean qu\u00e1 d\u00e0i (v\u00ed d\u1ee5, h\u01a1n 20-30 d\u00f2ng code), \u0111\u00f3 c\u00f3 th\u1ec3 l\u00e0 d\u1ea5u hi\u1ec7u b\u1ea1n n\u00ean t\u00e1ch n\u00f3 th\u00e0nh c\u00e1c h\u00e0m con nh\u1ecf h\u01a1n, m\u1ed7i h\u00e0m con \u0111\u1ea3m nhi\u1ec7m m\u1ed9t ph\u1ea7n c\u00f4ng vi\u1ec7c.<\/li>\n<li><strong>Th\u00eam Ch\u00fa th\u00edch (Comments) ho\u1eb7c Docstrings:<\/strong> \u0110\u1eb7c bi\u1ec7t v\u1edbi c\u00e1c h\u00e0m ph\u1ee9c t\u1ea1p ho\u1eb7c c\u00f3 logic kh\u00f4ng t\u01b0\u1eddng minh, h\u00e3y vi\u1ebft ch\u00fa th\u00edch ng\u1eafn g\u1ecdn ho\u1eb7c docstring (trong Python) \u0111\u1ec3 gi\u1ea3i th\u00edch h\u00e0m \u0111\u00f3 l\u00e0m g\u00ec, c\u00e1c tham s\u1ed1 c\u1ee7a n\u00f3 c\u00f3 \u00fd ngh\u0129a g\u00ec, v\u00e0 n\u00f3 tr\u1ea3 v\u1ec1 c\u00e1i g\u00ec. \u0110i\u1ec1u n\u00e0y c\u1ef1c k\u1ef3 h\u1eefu \u00edch cho vi\u1ec7c b\u1ea3o tr\u00ec sau n\u00e0y.<\/li>\n<li><strong>Tr\u00e1nh t\u00e1c d\u1ee5ng ph\u1ee5 kh\u00f4ng mong mu\u1ed1n (Side Effects):<\/strong> M\u1ed9t h\u00e0m t\u1ed1t th\u01b0\u1eddng nh\u1eadn \u0111\u1ea7u v\u00e0o qua tham s\u1ed1 v\u00e0 tr\u1ea3 k\u1ebft qu\u1ea3 qua <code>return<\/code>. H\u1ea1n ch\u1ebf vi\u1ec7c h\u00e0m thay \u0111\u1ed5i c\u00e1c bi\u1ebfn n\u1eb1m b\u00ean ngo\u00e0i n\u00f3 (bi\u1ebfn to\u00e0n c\u1ee5c) m\u1ed9t c\u00e1ch kh\u00f4ng c\u1ea7n thi\u1ebft, v\u00ec \u0111i\u1ec1u n\u00e0y c\u00f3 th\u1ec3 g\u00e2y ra c\u00e1c l\u1ed7i kh\u00f3 l\u01b0\u1eddng v\u00e0 l\u00e0m ch\u01b0\u01a1ng tr\u00ecnh kh\u00f3 g\u1ee1 r\u1ed1i h\u01a1n.<\/li>\n<li><strong>Th\u1ef1c h\u00e0nh th\u01b0\u1eddng xuy\u00ean:<\/strong> C\u00e1ch t\u1ed1t nh\u1ea5t \u0111\u1ec3 th\u00e0nh th\u1ea1o vi\u1ec7c s\u1eed d\u1ee5ng h\u00e0m l\u00e0 th\u1ef1c h\u00e0nh li\u00ean t\u1ee5c. B\u1eaft \u0111\u1ea7u v\u1edbi nh\u1eefng h\u00e0m \u0111\u01a1n gi\u1ea3n, sau \u0111\u00f3 th\u1eed th\u00e1ch b\u1ea3n th\u00e2n v\u1edbi c\u00e1c h\u00e0m ph\u1ee9c t\u1ea1p h\u01a1n. H\u00e3y ngh\u0129 v\u1ec1 c\u00e1c t\u00e1c v\u1ee5 l\u1eb7p \u0111i l\u1eb7p l\u1ea1i trong code c\u1ee7a b\u1ea1n v\u00e0 th\u1eed \u0111\u00f3ng g\u00f3i ch\u00fang th\u00e0nh h\u00e0m.<\/li>\n<\/ol>\n<div style=\"background-color: #e6f2ff; border-radius: 10px; padding: 20px; margin: 20px 0; border: 1px solid #b3d9ff;\">\n<p>Khi b\u1ea1n \u0111\u00e3 vi\u1ebft xong c\u00e1c h\u00e0m v\u00e0 \u1ee9ng d\u1ee5ng c\u1ee7a m\u00ecnh, vi\u1ec7c t\u00ecm m\u1ed9t n\u1ec1n t\u1ea3ng \u1ed5n \u0111\u1ecbnh, t\u1ed1c \u0111\u1ed9 cao \u0111\u1ec3 ch\u1ea1y th\u1eed nghi\u1ec7m ho\u1eb7c tri\u1ec3n khai l\u00e0 r\u1ea5t quan tr\u1ecdng. \u0110\u1ec3 b\u1eaft \u0111\u1ea7u m\u1ed9t c\u00e1ch \u0111\u01a1n gi\u1ea3n v\u00e0 ti\u1ebft ki\u1ec7m, <a target=\"_blank\" rel=\"noopener noreferrer\" href=\"https:\/\/interdata.vn\/thue-hosting\/\">d\u1ecbch v\u1ee5 thu\u00ea Hosting<\/a> t\u1ea1i InterData l\u00e0 l\u1ef1a ch\u1ecdn l\u00fd t\u01b0\u1edfng v\u1edbi dung l\u01b0\u1ee3ng t\u1ed1i \u01b0u.<\/p>\n<p>N\u1ebfu \u1ee9ng d\u1ee5ng c\u1ee7a b\u1ea1n c\u1ea7n nhi\u1ec1u t\u00e0i nguy\u00ean v\u00e0 kh\u1ea3 n\u0103ng ki\u1ec3m so\u00e1t cao h\u01a1n, <a target=\"_blank\" rel=\"noopener noreferrer\" href=\"https:\/\/interdata.vn\/thue-vps\/\">d\u1ecbch v\u1ee5 thu\u00ea VPS<\/a> cung c\u1ea5p c\u1ea5u h\u00ecnh m\u1ea1nh m\u1ebd v\u00e0 ch\u1ea5t l\u01b0\u1ee3ng \u0111\u00e1ng tin c\u1eady. V\u1edbi c\u00e1c d\u1ef1 \u00e1n l\u1edbn \u0111\u00f2i h\u1ecfi s\u1ef1 linh ho\u1ea1t v\u01b0\u1ee3t tr\u1ed9i, <a target=\"_blank\" rel=\"noopener noreferrer\" href=\"https:\/\/interdata.vn\/cloud-server\/\">d\u1ecbch v\u1ee5 thu\u00ea Cloud Server<\/a> cao c\u1ea5p s\u1ebd \u0111\u00e1p \u1ee9ng t\u1ed1t nhu c\u1ea7u.<\/p>\n<p>T\u1ea5t c\u1ea3 d\u1ecbch v\u1ee5 t\u1ea1i InterData \u0111\u1ec1u v\u1eadn h\u00e0nh tr\u00ean ph\u1ea7n c\u1ee9ng chuy\u00ean d\u1ee5ng th\u1ebf h\u1ec7 m\u1edbi nh\u01b0 AMD EPYC Gen 3th, SSD NVMe U.2 v\u00e0 c\u00f4ng ngh\u1ec7 \u1ea3o h\u00f3a ti\u00ean ti\u1ebfn, mang l\u1ea1i hi\u1ec7u n\u0103ng cao v\u00e0 \u1ed5n \u0111\u1ecbnh.<\/p>\n<\/div>\n","protected":false},"excerpt":{"rendered":"<p>Mu\u1ed1n vi\u1ebft code kh\u00f4ng ch\u1ec9 ch\u1ea1y \u0111\u01b0\u1ee3c m\u00e0 c\u00f2n g\u1ecdn g\u00e0ng, d\u1ec5 b\u1ea3o tr\u00ec v\u00e0 t\u00e1i s\u1eed d\u1ee5ng hi\u1ec7u qu\u1ea3? Hi\u1ec3u r\u00f5 v\u1ec1 function (h\u00e0m) l\u00e0 \u0111i\u1ec1u b\u1eaft bu\u1ed9c! B\u00e0i vi\u1ebft &#8220;to\u00e0n t\u1eadp&#8221; n\u00e0y s\u1ebd d\u1eabn d\u1eaft b\u1ea1n \u0111i t\u1eeb \u0111\u1ecbnh ngh\u0129a c\u01a1 b\u1ea3n h\u00e0m l\u00e0 g\u00ec, ph\u00e2n t\u00edch s\u00e2u c\u00e1c l\u1ee3i \u00edch thi\u1ebft th\u1ef1c,<\/p>\n","protected":false},"author":2,"featured_media":27449,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-27441","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-hosting"],"_links":{"self":[{"href":"https:\/\/interdata.vn\/blog\/wp-json\/wp\/v2\/posts\/27441","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/interdata.vn\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/interdata.vn\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/interdata.vn\/blog\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/interdata.vn\/blog\/wp-json\/wp\/v2\/comments?post=27441"}],"version-history":[{"count":4,"href":"https:\/\/interdata.vn\/blog\/wp-json\/wp\/v2\/posts\/27441\/revisions"}],"predecessor-version":[{"id":27453,"href":"https:\/\/interdata.vn\/blog\/wp-json\/wp\/v2\/posts\/27441\/revisions\/27453"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/interdata.vn\/blog\/wp-json\/wp\/v2\/media\/27449"}],"wp:attachment":[{"href":"https:\/\/interdata.vn\/blog\/wp-json\/wp\/v2\/media?parent=27441"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/interdata.vn\/blog\/wp-json\/wp\/v2\/categories?post=27441"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/interdata.vn\/blog\/wp-json\/wp\/v2\/tags?post=27441"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}