在头文件 (.h) 中声明构造函数然后在类文件 (.cpp) 中定义的语法 C++
声明：本页面是StackOverFlow热门问题的中英对照翻译，遵循CC BY-SA 4.0协议，如果您需要使用它，必须同样遵循CC BY-SA许可，注明原文地址和作者信息，同时你必须将它归于原作者（不是我）：StackOverFlow
原文地址: http://stackoverflow.com/questions/14574143/
Warning: these are provided under cc-by-sa 4.0 license. You are free to use/share it, But you must attribute it to the original authors (not me):
StackOverFlow
Syntax of Declaring a Constructor in Header (.h) and then Defining in a Class File (.cpp) C++
提问by user2020058
If anyone could lay this out, I would appreciate it. Example of what I thought would work (assume the needed #include statements are there):
如果有人可以解决这个问题，我将不胜感激。我认为可行的示例（假设需要#include 语句）：
//.h file
class someclass(){}
//.cpp
someclass::
someclass(){
//implementation
// of
//class
};
回答by billz
someclass.h file
someclass.h 文件
#ifndef SOME_CLASS_H
#define SOME_CLASS_H
class someclass
{
public:
someclass(); // declare default constructor
private:
int member1;
};
#endif
someclass.cpp
某个类.cpp
someclass::someclass() // define default constructor
: member1(0) // initialize class member in member initializers list
{
//implementation
}
回答by Billy ONeal
Header:
标题：
//.h file
class someclass
{
someclass();
}; // <-- don't forget semicolon here
Source:
来源：
#include "someClass.h"
//.cpp
someclass::someclass()
{
// Implementation goes here
} // <-- No semicolon here
回答by Andy Prowl
You have to declarethe constructor in your class if you want to provide a definitionfor it. You are only doing the second thing.
如果要为其提供定义，则必须在类中声明构造函数。你只是在做第二件事。
Also, your original class definition contains some mistakes: no parentheses are needed after the class name, and a semicolon is needed after the final curly brace.
此外，您的原始类定义包含一些错误：类名后不需要括号，最后一个大括号后需要分号。
class someclass
{
someClass(); // Here you DECLARE your constructor
};
...
someclass::someclass() // Here you DEFINE your constructor
{
...
}
