#define _CRT_SECURE_NO_WARNINGS 1
#include<stdio.h>
void swap1(int* pa, int* pb)
{
  int temp = 0;
  temp = *pa;
  *pa = *pb;
  *pb = temp;
}
int main()
{
  int a = 10;
  int b = 20;
  printf("%d %d\n", a, b);
  swap1(&a, &b);
  printf("%d %d\n", a, b);
 return 0;
}