程序风格的要素-C++风格指南
原著:Neill Kipp
翻译:Panic
2005年3月30日
译者序:这是一篇写于1996年1月23日的文章,到现在已经有9个年头了,很陈旧,有可能跟不上形势,但是有些东西仍然值得现在的开发者学习,我翻译这篇文字仅供读者参考。
原文链接:http://www.gamedev.net/reference/articles/article708.asp
文件
头文件有".h"后缀。头文件包含类(class),结构(struct),和联合(union)的声明,枚举(enum)的声明,#define,typedef。
实现文件有一个".cc" (UNIX) 或者".cpp" (Windows, DOS)后缀。实现文件包括函数和方法的实现。
在头文件和源代码文件中安排一个页眉。页眉可以包含标题,作者,日期,和一些工程的信息,比如这个文件是配合整个工程的。
一些名字
通用C++字符的名字:
(注:这些都是符号的英文原名,目前并没有完全标准化的汉语词汇对应,所以后面的翻译只是个人建议)
{
open brace, open curly 左花括号
}
close brace, close curly 右花括号
(
open parenthesis, open paren 左圆括号
)
close parenthesis, close paren 右圆括号
[
open bracket 左方括号
]
close bracket 右方括号
.
period, dot 句号,点
!
exclamation point, bang, not 叹号,否
|
bar, vertical-bar, or, or-bar (actually a "vertical virgule") 竖线,按位或
&
ampersand, and, reference, ref 和,按位与,引用,取地址
*
asterisk, multiply, star, pointer 星号,乘号,星,指针
/
slash, divide 斜线,除号
//
slash-slash, comment 双斜线,注释符
#
pound 井号 (宏:#,参考
backslash, (sometimes "escape") 反斜线,(有时候做转义符)(还有一个:续行符)
~
tilde 按位取反
基本类型 "char" 通常发音是"charcoal."的首音节。有时念作 "care" 或者 "car."
名字和排版
命名约定的名字
interspersed_underscores 中间下划线
lowercaseMixedCapital 小写混合(首字母)大写;
CapitalMixedCapital (首字母)大写混合(首字母)大写;
ALL_UPPERCASE 全部大写
命名约定的应用
enumeration_item_name 枚举,小写加下划线;
variableName 变量,小写前缀加首字母大写后缀;
TypeName, ClassName, MethodName() 类型名,类名,方法名,首字母大写前后缀;
UnixFileName.cc Unix/Linux文件名:每个单词首字母大写;
dosfn.cpp windows/dos文件名:全部小写;
POUND_DEFINES 宏定义,全部大写;
自成档代码(也就是没有文档,仅靠注释和代码说明的源代码文件)
程序中为每个名字使用完整拼写.
避免直接使用数字(Magic number)
不允许出现除了0(有时也包括1)之外的数字常量. 使用常变量或者宏定义(#defines).
空白
空格(按空格键得到) ;
新行(按回车键得到) ;
制表符(tab) (用8个空格代替) ;
空白和排版
左花括号之后, 每行缩进4个空格直到对应的右花括号出现.;
如果if, while, 或 for 后面没有跟花括号, 下一行缩进两个空格;
冒号结尾的语句,反向缩进两个空格(public, case);
保留字(if, else, class, struct) 前后要加1个空格除非已经因为新行或者特殊标点做了缩进;
运算符和比较符前后要有一个空格 (除了!之外);
指针变量 (&,*) 声明的时候要前后加一个空格;
指针变量 (&,*) 在表达式中,前面(不是后面)要加一个空格llowed) ;
左圆括号后要加一个空格;
换行
在下面这些关键字后的左花括号后要换行: class, struct, union, enum, method, function (而不是:
if, else, do, for, while, switch --- 这些的花括号后只要1个空格.)
方法(method),函数( function), if, else, do, for, while, switch的右花括号后要换行;
class, struct, union的右花括号后要换行并插入新空行。.(原文有写Semi-colon,不理解含义);
左花括号后要换行.
注释
注释总是从当前缩进开始 "//" 然后紧接一个空格;
注释中不允许其他注释;
注释要加在注释的对象之后. (译者注:原文 Comments always preceed the construct they address
);
注释中使用完整语句;
用于声明的时候,注释可以使用祈使句;
上面这些,是你的代码看起来舒服的指南,也是你的代码更具可读性的指南.
头文件示例:
// MODULE NAME: ClassName.h
// PROJECT: CS1344-1,2 Course Notes
// AUTHOR: Neill Kipp
// DATE: January 1, 1996
// DESCRIPTION: This file presents examples of naming and
// indentation style in a C++ class declaration. This title
// information is minimal.
// The following prevents files from being included
// twice. It is a naming exception designed to emulate a file name
// (period is not a name character; underscore is).
#ifndef ClassName_h
#define ClassName_h
// This directive includes the superclass declaration.
#include "super.h"
// This directive includes another class declaration.
#include "other.h"
// The comment for an enumeration declaration precedes the declaration.
enum OverflowState
{
// Each item''s comment precedes it at the same indentation as the item.
no_overflow,
// Follow the last item with a comma;
// it helps avoid syntax errors when adding or rearranging items.
overflow_occurred,
};
// This class shows how naming conventions and comments are used in a
// simple class declaration. Whitespace precedes and follows reserved
// words (like "public").
class ClassName
{
// After a brace, indent four spaces.
// The description of the variable "memberData" goes here.
int memberData;
// If a line ends in single colon, reverse-indent two spaces.
public:
// The constructor gives initial values to member data.
ClassName();
// The destructor guarantees clean deallocation.
// The tilde (~) is part of the method name. It is not an operator.
~ClassName();
// This method increments the member variable by the value in "howMuch"
// and returns TRUE if overflow is detected (FALSE otherwise). Method
// comments tell what the method does, what the arguments are,
// and what the method returns.
OverflowState IncrementMemberVariable( int howMuch);
// Prints message about overflow.
void ShowOverflow( OverflowState overflow);
};
#endif
源代码文件示例:
// MODULE NAME: ClassName.cc
// PROJECT: CS1344-1,2 Course Notes
// AUTHOR: Neill Kipp
// DATE: January 1, 1996
// DESCRIPTION: This file presents examples of naming and
// indentation style in a C++ class implementation. This title
// information is minimal.
// This directive includes header information for the "ClassName" class.
#include "ClassName.h"
ClassName::ClassName()
{
// Initialize member data (statement comments are in the imperative,
// and preceed the statement). Suggestion: write the comments first, then
// write the code.
memberData = 0;
}
// The return type appears on the first line,
// followed by the class name colon-colon on the second,
// and finally the method name on the last. Then a newline, an open brace
// and then indent. Notice the space after the open parenthesis. It helps
// the eye catch the type name.
OverflowState
ClassName::IncrementMemberVariable( int howMuch)
{
// Check the overflow condition.
if ( TOO_BIG - memberVariable > howMuch) {
// If overflow, return that overflow occurred.
return overflow_occurred;
} else {
// Otherwise, return overflow is ok.
return overflow_none;
}
}
// This code implements the ShowOverflow method.
void
ClassName::ShowOverflow( OverflowState overflow)
{
// Switch is a reserved word. It is followed by a space.
switch ( overflow) {
// Lines ending in a colon reverse indent two spaces.
case no_overflow:
// Display message about no overflow.
cout << "No overflow occurred.\n";
break;
case overflow_occurred:
// Display message that overflow occurred.
cout << "Warning: overflow occurred.\n";
break;
}
}
其他例子:
// Note the spacing and indentation in the for statement.
for ( whichItem = 0; whichItem < BIG_NUMBER; whichItem++) {
DoSomething( whichItem);
}
// Bang is not followed by a space.
while ( !SemaphoreOK()) {
DoWaitForSemaphore( LONG_TIME);
}