swap3.c

C Primer Plus(第五版)中文版源码,I hope it will help you much

/* swap3.c -- using pointers to make swapping work */
#include <stdio.h>
void interchange(int * u, int * v);

int main(void)
{
    int x = 5, y = 10;

    printf("Originally x = %d and y = %d.\n", x, y);
    interchange(&x, &y);  /* send addresses to function  */
    printf("Now x = %d and y = %d.\n", x, y);

    return 0;
}

void interchange(int * u, int * v)
{
    int temp;

    temp = *u;       /* temp gets value that u points to */
    *u = *v;
    *v = temp;
}