{"id":25218,"date":"2024-03-16T04:32:06","date_gmt":"2024-03-16T04:32:06","guid":{"rendered":"https:\/\/www.silicloud.com\/blog\/how-to-declare-and-define-a-c-function\/"},"modified":"2024-03-22T05:38:33","modified_gmt":"2024-03-22T05:38:33","slug":"how-to-declare-and-define-a-c-function","status":"publish","type":"post","link":"https:\/\/www.silicloud.com\/blog\/how-to-declare-and-define-a-c-function\/","title":{"rendered":"How to declare and define a C++ function?"},"content":{"rendered":"

There are several ways to declare and define functions in C++.<\/p>\n

    \n
  1. Function declaration and definition are placed in the same file.<\/li>\n<\/ol>\n
    \/\/ \u51fd\u6570\u58f0\u660e<\/span>\r\n\u8fd4\u56de\u503c\u7c7b\u578b \u51fd\u6570\u540d(\u53c2\u6570\u5217\u8868);\r\n\r\n\/\/ \u51fd\u6570\u5b9a\u4e49<\/span>\r\n\u8fd4\u56de\u503c\u7c7b\u578b \u51fd\u6570\u540d(\u53c2\u6570\u5217\u8868) {\r\n    \/\/ \u51fd\u6570\u4f53<\/span>\r\n}\r\n<\/code><\/pre>\n
      \n
    1. Function declaration and definition are separated, with declaration placed in the header file and definition placed in the source file.<\/li>\n<\/ol>\n
      \/\/ \u51fd\u6570\u58f0\u660e<\/span>\r\n\u8fd4\u56de\u503c\u7c7b\u578b \u51fd\u6570\u540d(\u53c2\u6570\u5217\u8868);\r\n<\/code><\/pre>\n
      Source file:<\/p>\n
      \/\/ \u51fd\u6570\u5b9a\u4e49<\/span>\r\n\u8fd4\u56de\u503c\u7c7b\u578b \u51fd\u6570\u540d(\u53c2\u6570\u5217\u8868) {\r\n    \/\/ \u51fd\u6570\u4f53<\/span>\r\n}\r\n<\/code><\/pre>\n
        \n
      1. Use default parameters:<\/li>\n<\/ol>\n
        \/\/ \u51fd\u6570\u58f0\u660e<\/span>\r\n\u8fd4\u56de\u503c\u7c7b\u578b \u51fd\u6570\u540d(\u53c2\u6570\u5217\u8868 = \u9ed8\u8ba4\u503c);\r\n\r\n\/\/ \u51fd\u6570\u5b9a\u4e49<\/span>\r\n\u8fd4\u56de\u503c\u7c7b\u578b \u51fd\u6570\u540d(\u53c2\u6570\u5217\u8868) {\r\n    \/\/ \u51fd\u6570\u4f53<\/span>\r\n}\r\n<\/code><\/pre>\n
          \n
        1. Utilize function templates.<\/li>\n<\/ol>\n
          \/\/ \u51fd\u6570\u58f0\u660e\uff08\u51fd\u6570\u6a21\u677f\uff09<\/span>\r\ntemplate<\/span> <typename<\/span> T>\r\n\u8fd4\u56de\u503c\u7c7b\u578b \u51fd\u6570\u540d(\u53c2\u6570\u5217\u8868);\r\n\r\n\/\/ \u51fd\u6570\u5b9a\u4e49\uff08\u51fd\u6570\u6a21\u677f\uff09<\/span>\r\ntemplate<\/span> <typename<\/span> T>\r\n\u8fd4\u56de\u503c\u7c7b\u578b \u51fd\u6570\u540d(\u53c2\u6570\u5217\u8868) {\r\n    \/\/ \u51fd\u6570\u4f53<\/span>\r\n}\r\n<\/code><\/pre>\n
          Important notes:<\/p>\n
            \n
          1. The function name can consist of letters, numbers, and underscores, but cannot start with a number.<\/li>\n
          2. The return type can be any valid data type, including primitive data types, custom types, and pointer types.<\/li>\n
          3. The parameter list can contain zero or more parameters, each parameter consists of a parameter type and parameter name, and multiple parameters are separated by commas.<\/li>\n
          4. Function declarations can omit parameter names and only keep parameter types, for example: int add(int, int);.<\/li>\n
          5. If a function does not return a value, the return type should be void.<\/li>\n
          6. If a function has no parameters, the parameter list is empty, for example: void printHello();.<\/li>\n
          7. Function templates allow functions to be defined and used in a generic way, allowing specific types to be specified when called based on actual needs.<\/li>\n<\/ol>\n","protected":false},"excerpt":{"rendered":"
            There are several ways to declare and define functions in C++. Function declaration and definition are placed in the same file. \/\/ \u51fd\u6570\u58f0\u660e \u8fd4\u56de\u503c\u7c7b\u578b \u51fd\u6570\u540d(\u53c2\u6570\u5217\u8868); \/\/ \u51fd\u6570\u5b9a\u4e49 \u8fd4\u56de\u503c\u7c7b\u578b \u51fd\u6570\u540d(\u53c2\u6570\u5217\u8868) { \/\/ \u51fd\u6570\u4f53 } Function declaration and definition are separated, with declaration placed in the header file and definition placed in the source file. \/\/ \u51fd\u6570\u58f0\u660e […]<\/p>\n","protected":false},"author":11,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_import_markdown_pro_load_document_selector":0,"_import_markdown_pro_submit_text_textarea":"","footnotes":""},"categories":[1],"tags":[],"class_list":["post-25218","post","type-post","status-publish","format-standard","hentry","category-uncategorized"],"yoast_head":"\nHow to declare and define a C++ function? - Blog - Silicon Cloud<\/title>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/www.silicloud.com\/blog\/how-to-declare-and-define-a-c-function\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"How to declare and define a C++ function?\" \/>\n<meta property=\"og:description\" content=\"There are several ways to declare and define functions in C++. Function declaration and definition are placed in the same file. \/\/ \u51fd\u6570\u58f0\u660e \u8fd4\u56de\u503c\u7c7b\u578b \u51fd\u6570\u540d(\u53c2\u6570\u5217\u8868); \/\/ \u51fd\u6570\u5b9a\u4e49 \u8fd4\u56de\u503c\u7c7b\u578b \u51fd\u6570\u540d(\u53c2\u6570\u5217\u8868) { \/\/ \u51fd\u6570\u4f53 } Function declaration and definition are separated, with declaration placed in the header file and definition placed in the source file. \/\/ \u51fd\u6570\u58f0\u660e […]\" \/>\n<meta property=\"og:url\" content=\"https:\/\/www.silicloud.com\/blog\/how-to-declare-and-define-a-c-function\/\" \/>\n<meta property=\"og:site_name\" content=\"Blog - Silicon Cloud\" \/>\n<meta property=\"article:publisher\" content=\"https:\/\/www.facebook.com\/SiliCloudGlobal\/\" \/>\n<meta property=\"article:published_time\" content=\"2024-03-16T04:32:06+00:00\" \/>\n<meta property=\"article:modified_time\" content=\"2024-03-22T05:38:33+00:00\" \/>\n<meta name=\"author\" content=\"Olivia Parker\" \/>\n<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n<meta name=\"twitter:creator\" content=\"@SiliCloudGlobal\" \/>\n<meta name=\"twitter:site\" content=\"@SiliCloudGlobal\" \/>\n<meta name=\"twitter:label1\" content=\"Written by\" \/>\n\t<meta name=\"twitter:data1\" content=\"Olivia Parker\" \/>\n\t<meta name=\"twitter:label2\" content=\"Est. reading time\" \/>\n\t<meta name=\"twitter:data2\" content=\"1 minute\" \/>\n<script type=\"application\/ld+json\" class=\"yoast-schema-graph\">{\"@context\":\"https:\/\/schema.org\",\"@graph\":[{\"@type\":\"Article\",\"@id\":\"https:\/\/www.silicloud.com\/blog\/how-to-declare-and-define-a-c-function\/#article\",\"isPartOf\":{\"@id\":\"https:\/\/www.silicloud.com\/blog\/how-to-declare-and-define-a-c-function\/\"},\"author\":{\"name\":\"Olivia Parker\",\"@id\":\"https:\/\/www.silicloud.com\/blog\/#\/schema\/person\/3ff7b3da0e45ac5dbbef2502f3cea8d9\"},\"headline\":\"How to declare and define a C++ function?\",\"datePublished\":\"2024-03-16T04:32:06+00:00\",\"dateModified\":\"2024-03-22T05:38:33+00:00\",\"mainEntityOfPage\":{\"@id\":\"https:\/\/www.silicloud.com\/blog\/how-to-declare-and-define-a-c-function\/\"},\"wordCount\":190,\"commentCount\":0,\"publisher\":{\"@id\":\"https:\/\/www.silicloud.com\/blog\/#organization\"},\"inLanguage\":\"en-US\"},{\"@type\":\"WebPage\",\"@id\":\"https:\/\/www.silicloud.com\/blog\/how-to-declare-and-define-a-c-function\/\",\"url\":\"https:\/\/www.silicloud.com\/blog\/how-to-declare-and-define-a-c-function\/\",\"name\":\"How to declare and define a C++ function? 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