I dont get how command design pattern works in game development

Question

Maybe that's my lack of c++ knowledge or lack of programing skills, but i'm trying to understand command design pattern in c++ for game development. I'm reading this book (its literally called "Game Programing Patterns" and i quite like it), and i decided to use one of the design patterns in real code to see if i really get it. So i created this scrap code, which unsurprisingly doesnt work:

#include <iostream>


void jump() {
    //assume that this is some random
    //code that makes player jump
    //if console displays "Player jumps"
    //this means that this code works...
    std::cout << "Player jumps";
}
void fireGun() {
    //same thing as jump function
    //but its for fire gun
    std::cout << "Gun goes pew pew";
}

class Command
{
public:
    virtual ~Command(){}
    virtual void execute() = 0;
};

class JumpCommand : public Command
{
public:
    virtual void execute() { jump(); }
};

class FireCommand : public Command
{
public:
    virtual void execute() { fireGun(); }
};

class InputHandler
{
public:
    void handleInput();
    
    /// Methods to bind commands????

private:
    Command* buttonX_;
    Command* buttonY_;
};

void InputHandler::handleInput() {
    bool is_BUTTON_A_pressed = true; 
    //lets assume that this is a function that detects
    //if button a ir pressed and it returns true 
    //(meaning button a is pressed)
    if (is_BUTTON_A_pressed) buttonX_->execute();
}



int main() 
{
    InputHandler input;
    input.handleInput();
    return 0;
}

for those wondering here is the source from where i pulled out this design pattern example code: https://gameprogrammingpatterns.com/command.html

So the thing that confuses me the most is "Methods to bind commands" part (which i commented in code), i have a feeling like it has something to do with binding buttonX_ and buttonY_ to command, but thats it...

Answer 1

What your missing is binding buttonX_ and buttonY_ to do something. I think all you're missing is a constructor (or some other mechanism) that does something like this:

buttonX_ = new JumpCommand();
buttonY_ = new FireCommand();

Right now, they're not pointing to anything. Point them to something and you'll be happier.