在C++中使用成员函数指针
函数指针的语法相对比较复杂，成员函数指针则在此基础上进一步引入了类作用域限定。让我们来了解一下成员函数指针的写法。
首先回顾一下函数指针的使用方法。有这样一个函数：
double func(double x)
{
return 3.14 * x;
}
我们这样声明函数指针，并且进行调用：
double (*pfunc)(double x); pfunc = &func; cout << (*pfunc)(1.1) << endl;
指针的声明包括返回类型、指针名和函数的参数表，对于一个强类型的编译型语言，这些要素都必不可少。由于运算符优先级的规定，还要特别注意在适当的位置加上括号。
对于成员函数指针，就是增加了一个作用域限定。
首先有一个类A，包含几个类型相同的函数。
class A
{
public:
void f1(int x)
{
cout << "f1:" << x << endl;
}
void f2(int x)
{
cout << "f2:" << x << endl;
}
void f3(int x)
{
cout << "f3:" << x << endl;
}
};
然后类B的对象会调用类A的对象的成员函数，然而具体调用哪一个还不知道，我们通过指针的方式来实现，在运行时将指针指向一个类型兼容的成员函数。
class B
{
public:
void (A::*pf) (int x); //注意作用域运算符和*的次序，括号不能省略
void callF(int x)
{
A a;
(a.*pf)(x);
}
};
我们在外部实例化B的对象，然后为B的成员函数指针赋值，确定将要调用的是哪一个函数。
cout << "Hello world!" << endl; B b; b.pf = &A::f2; b.callF(5);
Dec 12, 2011 10:38:55 PM
都已经用函数指针了为何不用functor?
Dec 12, 2011 10:40:24 PM
@zhjx: 后面的call我没有看见
当我没说罢.........
Dec 05, 2022 10:24:22 PM
In C++, member function pointers allow you to store the address of a member function in a variable. This can be useful when you want to call a member function from a different part of your code, or from a different object. To use member function pointers, you first need to declare a function pointer variable with the Lab grown diamonds same signature as the member function you want to store. For example, if you have a class called MyClass with a member function called MyFunction, you would declare a function pointer like this: MyClass::MyFunctionPtr MyFunctionPtr; You can then store the address of MyFunction in MyFunctionPtr like this: MyFunctionPtr = &MyClass::MyFunction;
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Very good blog post.Much thanks again. Cool