Thread: pointers and functions

you may want to look up polymorphism.

Hi,

Now i need onclick function for it, i think it sould be pointer type variable, so i can apply something like this is main.cpp: button.onclick=&mycustomfunction. how do i do that and how do i define the variable?

Here is an example of using pointers to functions:

Code:

#include <iostream>
using namespace std;

class MyButton
{
public:
	
	int x;
	int y;
	double (*onclick)(int a);

	MyButton()
	{
		x = 0;
		y = 0;
		onclick = 0;
	}

	          
};

double myCustomFunc(int a)
{
	cout<<a<<endl;
	return a + 2.0;
}


int main()
{
	MyButton b;
	b.onclick = myCustomFunc;

	double result = b.onclick(10);

	return 0;
}

A pointer to a function must reflect the type of the function, and the type of a function includes the return type and the parameter types. You should note that myCustomFunc is not a member function of MyButton and therefore it does not have access to MyButton member variables unless they are public.