C++ Programming Style.docx

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1 C++ Programming Style (C++ 编码规范 ) Last Modified: Hongfei Yan 目的 书写格式规范 标示符命名规范 文档规范 模块组织规范 一般性原则 = 目的 = 增强代码的可读性, 从而使得系统具有更少的 Bug 和更高的健壮性 涉及到程序的书写格式 (Code appearance/layout) 标示符命名 (Naming) 文档规范 ( 注释 ) 模块组织规范和一般性原则 = 书写格式规范 = 1. place the brace at the end of the line that controls entry into the block ( 左花括号写在行尾代码块的开始 ) If-else statements: if (condition) { if (condition) { else { if (condition) { else if (condition) { else { For-loop statements: for (initialization; condition; update) { An empty for statement should have the following form: for (initialization; condition; update) ; 1

2 While statements: while (!done) { statements (); Do-while statements: do { while (condition); Switch statements switch (condition) { case ABC : case DEF : break; case XYZ : break; default : 2.Use a single space to separate the keywords, parentheses, and curly braces in conditional statements. ( 条件语句中, 比如 if() for() while() try(), 使用一个空格分隔关键词, 括号和花括号 ) for.(...).{ // 不使用 hard TAB 配置好编辑器, 把对齐缩进时敲入的 hardtab 保存为空格 缩进使用 4 个空格 VIM :set tabstop=4 :set expandtab 4. White space - Conventional operators should be surrounded by a space character. - C++ reserved words should be followed by a white space. - Commas should be followed by a white space. - Colons should be surrounded by white space. - Semicolons in for statments should be followed by a space character. a = (b + c) * d; // NOT: a=(b+c)*d while (true) { // NOT: while(true)... dosomething (a, b, c, d); // NOT: dosomething(a,b,c,d); 2

3 case 100 : // NOT: case 100: for (i = 0; i < 10; i++) { // NOT: for(i=0;i<10;i++){... = 标示符命名规范 = 1. 使用有意义的, 一致的名字, 不使用缩写 if (age < RetirementAge) { yearstoretirement = RetirementAge - age; else { yearstoretirement = 0; 2. 类, 常数, 结构, 枚举和类型名使用 UpperCamelCase enum BackgroundColor { None, Red, Green, Blue ; const int FixedWidth = 10; class BankAccount { //... ; typedef list<bankaccount> Portfolio; 3. 函数名, 变量名, 参数名, 缩略语使用 lowercamelcase class Customer { public: void setaddress(const Address& address); ; int fixedwidth = 10; // it s a variable, not a constant XMLString -> XmlString loadxmldocument() -> loadxmldocument() 4. 定义对象的类 结构和类型名使用名词 class Customer { //... ; typedef int Dollars; 5. 变量名使用名词 class Customer { private: Address m_billingaddress; Address m_shippingaddress; Phone m_daytimephone; 3

4 Orders m_openorders; ; 6. 函数名使用动词 class Account { public: void withdraw(int amount); void deposit(int amount); ; 7. 不要省略参数名 MyClass (int); // Bad MyClass (float meaningfulname); // Good 8. Iterator variables should be called i, j, k etc. for (int i = 0; i < ntables; i++) { : 9. The prefix is should be used for boolean variables and methods. isset, isvisible, isfinished, isfound, isopen = 文档规范 = 1. 文件头的版权和描述信息 : 每一个头文件 (.hpp) 包含一个如下所示的文件头 : /** filename Brief description goes here. Gailun Zhang<zgl@gmail.com> 0.1 * 1. created on * 2. write your history2 here */ 2. 使用 block 注释描述代码接口 (program interface): 类定义中每一个成员函数前都包含如下注释 : /** Brief description goes here. argone Description of first function argument. argtwo Description of second function argument. Description of returned value. */ 3. 不在行尾写注释 double length = 0; // vector length. BAD Comments should be included relative to their position in the code while (true) { // NOT: while (true) { // Do something // Do something something(); something(); 4

5 = 模块组织规范 = 分离接口与实现是 C++ 模块管理的基本思想 概念上的分离应该保证 : 用户只看到他所关心的接口, 而看不到实现 1. 使用类名作文件名一般一个文件只包含一个 public 的类 文件名使用类名, 并使用同样的大小写风格 (UpperCamelCase) 对应的头文件扩展名为.h, 实现文件扩展名为.cpp 2. 头文件中不使用全局作用域的 using 或 using namespace 语句在非全局作用域内, 可自由使用 using 语句, 比如自己定义的 namespace 中, 和.cpp 的类实现文件中, 它们不会影响其它的代码 3. 在头文件内部而不是在外部写包含检查建议使用 _ModulePrefix_filename_INCLUDED_ 这样的命名作为 include guard 的名称 // in foo.h #ifndef APP_FOO_H_INCLUDED_ #define APP_FOO_H_INCLUDED_ // contents of the #endif = 一般性原则 = 1. 初始化所有变量 // Acceptable: Create an empty path char path[max_path]; path[0] = \0 ; // Better: Create a zero-filled path char path[max_path] = { \0 ; 2. 一行不要太长, 不能超过显示区域. 太长则应折行, 折行最好发生在运算符前面. File content must be kept within 80 columns. 80 columns is a common dimension for editors, terminal emulators, printers and debuggers, and files that are shared between several people should keep within these constraints. It improves readability when unintentional line breaks are avoided when passing a file between programmers. 3."Hungarian" prefixes: m_ Variable is a member of class. a array c count / number of cb count bytes / number of bytes d Data type double dw Data type double word e element of an array b boolean g_ global variable s_ Static variable l long data type. i.e. "long int" n int 5

6 u unsigned str C++ GNU template data type "string" p pointer lp pointer to long data type ch C character sz Zero terminated string. char[] min Lowest value first First element cmd Command CAbcXyz abcxyz 4. 尽量以 const 取代 #define 5. 尽量以 <iostream> 取代 <stdio.h> 参考文献 [Geosoft, 2011] Geotechnical Software Services, C++ Programming Style Guidelines, [Yang, et al., 2007] TFS-C++ Coding Standards, [encyclopedia, 2007] Programming style, [yolinux, 2007] [Meyers, 1998] Scott Meyers, Effective C++: 50 Specific Ways to Improve Your Programs and Design (2nd Edition): Addison-Wesley,