39. Button Press Callback

#include <iostream>
#include <string>
using namespace std;

void onPressA() { cout << "Button A pressed\n"; }
void onPressB() { cout << "Button B pressed\n"; }

void simulatePress(void (*callback)()) {
    callback(); // call the function passed in
}

int main() {
    string input;
    cin >> input;

    if (input == "A") {
        simulatePress(onPressA);
    } else if (input == "B") {
        simulatePress(onPressB);
    }

    return 0; }

Solution Details

• simulatePress takes a function pointer callback.
• When called, it runs whichever function is passed (onPressA or onPressB).
• This shows how the program can register different behaviors dynamically.
  
   

👉 In simple words:
 Think of the button as a doorbell. The callback is who answers the door. You can change who answers without changing the doorbell itself.

Significance for Embedded Developers

• This is exactly how interrupts and callbacks work in firmware.
   
• Example:
  • A GPIO button press triggers an interrupt.
  • The programmer sets a callback that runs when the interrupt fires.
     
• This makes code modular — you can reuse the same button code but change the action as needed.