c++ - '*' token : Pointer to Member Functions 之前的预期不合格 ID

Question

我正在尝试运行此代码，但无法理解导致错误的原因。

#include <iostream>
using namespace std;

class Shape
{
    public:
        void show ( float ) { cout << "Hello"; }
};

int main ( )
{

    void (Shape::*FPtr2) (float) = &Shape :: show;
    (Shape::*FPtr2)(1.1);

    return 0;
}

Answer 1

调用非静态成员函数需要一个对象。通过指向成员函数的指针调用非静态成员函数也需要一个对象。

#include <iostream>
using namespace std;

class Shape
{
    public:
        void show ( float ) { cout << "Hello"; }
};

int main ( )
{
    void (Shape::*FPtr2) (float) = &Shape :: show;
    Shape myShape;  // here is my object
    (myShape.*FPtr2)(1.1);  // here is the call to the object's show function via pointer
    return 0;
}