在 C++ 中使用非静态 class 函数的函数

Question

I have a class containing several functions, and I would like to be able to use functions of these functions. When I try to do something like the code below, I keep getting the compiler error message "invalid use of non-static member function".

class MyClass{
    protected:
        void f(int a, int b);
        void g(int num);
        void do_something_with_function(int count, void func(int, int));
        ...
        ...


};

void MyClass::do_something_with_function(int count, void func(int, int)){
    for(int i=0; i<count; i++){
        for(int x=0; x<5; x++){
            for(int y=0; y<3; y++){
                func(x,y);
            }
        }
    }
}

void MyClass::f(int a, int b){
    std::cout<<"a="<<a<<", b="<<b<<std::endl;
}

void MyClass::g(int num){
    do_something_with_function(num, f);
}

Is there a way to get this to work without making f (and all of the functions on which f depends) static?

Answer 1

Yes, you just need to accept a pointer to member function, not a regular function.

Change the definition to:

void MyClass::do_something_with_function(int count, 
                                         void (MyClass::*func)(int, int)) {
  // ...
  func(1, 2); // and use func
}

(and the declaration must be changed as well, of course), and call the function like this:

do_something_with_function(num, &MyClass::f);

Here's a demo .