C++ Callbacks

cb_for_dan.cc

#include <stdio.h>

// Typedef for functions like "hi"
typedef int (*FPN)(int);
// Typedef for functions like "bye"
typedef int (*sFPN)(int, FPN);

// A function that takes an int num, and returns an int (num + 1)
int hi(int num) {
  return num + 1;
}

// A function that cakes an int num and a callback cb, returns cb(num) + 1
// The callback should be a function that takes an int and returns an int
int bye(int num, FPN callback) {
  return callback(num) + 1;
}

// Main
int main(int argc, char **argv) {
  // Create a local reference to the function bye, and name it bye_local 
  sFPN bye_local = *bye;

  // Stores the address of the function hi as a pointer to a void
  FPN bye_callback = *hi;

  // Calls bye (Stored in bye_local ) with the callback to hi (stored in bye_callback)
  printf("hi %d\n", bye_local (1, bye_callback));
  return 1;
}