swap3.c

c primer plus 第五版 的源代码

/* 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;
    printf("Originally x = %d and y = %d.\n", *u, *v);

    temp =u;       /* temp gets value that u points to */
    u = v;
    v = temp;
     printf("Now x = %d and y = %d.\n", *u, *v);

}