#include <stdio.h>


int flip(int *a, int *b) {

  int tmp;

  tmp = *a;
  *a = *b;
  *b = tmp; 

  printf("In function values: a=%d; b=%d\n", *a,*b);
  return 1;
}

int main() {

  int first, second;
  int result;

  first = 10;
  second = 31;
  printf("Old values: first = %d; second = %d\n", 
            first, second); 

  result = flip(&first, &second);

  printf("New values: first = %d; second = %d\n", 
            first, second); 

  return 0;
}