Set function for an instance of a class

Question

Hello !
I am currently working on a UI tool in C++ using SDL2 (already made one in Python with OOP and Pygame).
I want to make buttons which each has a custom function named "click_event".
I want to pass this function as an argument in the constructor "Button", but it gives me an error...

class Button{
int x, y;
int width, height;
void click_event();
[...]
public :
Button(int x, [...], void (*click_event)()){
this->x = x;
[...]
this->click_event = *click_event; // This gives me an error [*]
}
[...]
};

[*] : error: invalid use of member 'void Button::click_event()' (did you forget the '&' ?)

void (*click_event)() is a pointer to the function, right ? So, *click_event is the function ? Please correct me if I'm wrong...

Have a good day !

Answer 1

I don't think you need void there twice.
In your 4th line you have "void click_event();", so leave out the void in line 7. See if that works.

Answer 2

The line 7 defines a function, so i'm pretty sure we need to specify the type for every arguments. I also tried, it doesn't work :/

Answer 3

I found a solution ! (which I don't fully understand though... If someone could explain me I would be grateful !)

class Button{
int x, y;
int width, height;
void (*click_event)(); // changed, I don't really understand what's happening here
[...]
public :
Button(int x, [...], void click_event()){ // changed
this->x = x;
[...]
this->click_event = click_event; // changed
}
[...]
};

I also found out we can use click_event without any 'decorations' around such as '&' or '*' (as a classic function).