#include <stdio.h>

int exchange(int *a, int *b) 
{
    int temp = *a;
    *a = *b;
    *b = temp;
}

int main() 
{
    int a, b;
    printf("输入第一个数字: ");
    scanf("%d", &a);
    printf("输入第二个数字: ");
    scanf("%d", &b);

    printf("交换前: a = %d, b = %d\n", a, b);
    exchange(&a, &b);
    printf("交换后: a = %d, b = %d\n", a, b);

    return 0;
}