#include <stdio.h>

int square(int number);
void recursionAndThen(int countDown, void *myFunction);
void printName();

int main(void) {
  printf("Hello World\n");
  int ivar = 1;
  if( ivar == square(ivar) ) {
    printf("ivar has no changes");
  }

  recursionAndThen(5, &printName);

  return 0;
}

void printName() {
  int i = square(9);
  printf("9 squared is %d\n", i);
}

int square(int number) {
  return number * number;
}

void recursionAndThen(int countDown, void *aFunction) {
  if(countDown > 0) {
   countDown = countDown - 1;
   printf("count is: %d\n", countDown);
   recursionAndThen(countDown, aFunction);
   return;
  }

  void (* newFunction)() = aFunction;
  (*newFunction)();
}