程序代码：

#include<stdio.h>
int main()
{
    int a, b;
    void exchange(int x, int y);
    printf("请输入两个整数：");
    scanf("%d %d", &a, &b);
    if (a>b)exchange(a, b);//满足a<b 
    printf("按从小到大的顺序输出：%d %d\n", a, b);
    return 0;
}
void exchange(int x, int y)
{
    int z;
    z = y; y = x; x = z;//  x=z
    printf("按从小到大的顺序输出：%d %d\n", x, y);
}