C ++类与静态指针 [英] C++ class with static pointer

问题描述

我不太理解指针和引用，但我有一个类，静态方法和变量，将引用从主和其他类。我有一个变量定义在main（），我想传递给这个类中的一个变量与静态函数。我想让这些函数改变在main（）范围内看到的变量的值。

I don't understand pointers and references very well yet, but I have a class with static methods and variables that will be referenced from main and other classes. I have a variable defined in main() that I want to pass to a variable in this class with static functions. I want those functions to change the value of the variable that is seen in the main() scope.

这是我想做的一个例子，但我获取编译器错误...

This is an example of what I am trying to do, but I get compiler errors...

class foo
{
    public:

    static int *myPtr;

    bool somfunction() {
        *myPtr = 1;
        return true;
    }
};

int main()
{
    int flag = 0;
    foo::myPtr = &flag;

    return 0;
}

推荐答案

类外的变量：

//foo.h
class foo
{
    public:

    static int *myPtr; //its just a declaration, not a definition!

    bool somfunction() {
        *myPtr = 1;
        //where is return statement?
    }
};  //<------------- you also forgot the semicolon


/////////////////////////////////////////////////////////////////
//foo.cpp
#include "foo.h"  //must include this!

int *foo::myPtr; //its a definition

除此之外，您还忘记了上面注释中指出的分号， somefunction 需要返回 bool 值。

Beside that, you also forgot the semicolon as indicated in the comment above, and somefunction needs to return a bool value.

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