A simple example of function pointers

function_pointer.cpp

#include <iostream>

/** A simple example of function pointers */

// some globally-defined functions that take an int and return an int
int foo(int a) {
  std::cout << "foo: a is " << a << std::endl;
  return 42;
}

int bar(int a) {
  std::cout << "bar: a is " <<  a << std::endl;
  return 1337;
}

int main(int argc, char* argv[]) {
  // call foo and bar like a normal person
  int rfoo = foo(3);
  int rbar = bar(3);

  // create a pointer to a function that takes an int and returns an int,
  // and call that pointer "pf"
  //
  // the syntax is like declaring a function:
  //
  // function:         [return type] [function name]([argument type list])
  // function pointer: [return type] (*[pointer name])([argument type list])
  int (*pf)(int);

  // make pf point to foo
  pf = &foo;

  // call it. wow!
  (*pf)(12);

  // now make pf point to bar
  pf = &bar;

  // now call that!
  (*pf)(13);

  return 0;
}