指针实现交换两个数字的大小

指针实现交换两个数字的大小2010-10-07 51cto xufengnju

#include <stdlib.h>
#include <stdio.h>
void swap（int *x,int *y）
{
    int tmp;
    tmp = *x;
    *x = *y;
    *y = tmp;

}
int main（void）
{   
    int *x,*y;
    x = （int *）malloc（sizeof（int））;
    y = （int *）malloc（sizeof（int））;
    /*check if malloc is successful*/
    if（x == NULL || y == NULL）
    {
        return -1;
    }
    else
    {
        printf（"The address x pointed to is %d
",x）;
        printf（"The address y pointed to is %d
",y）;
        *x = 1;
        *y = 2;
        swap（x,y）;/*call function*/
        printf（"The address x pointed to is %d
",x）;
        printf（"The address y pointed to is %d
",y）;
        printf（"x is %d 
",*x）;
        printf（"y is %d 
",*y）;
        free（x）;
        free（y）;
        x = NULL;
        y = NULL;
        int a = 100;
        int b = 200;
        swap（&a,&b）;/*call function*/
        printf（"a is now %d.
",a）;
        printf（"b is now %d.
",b）;
        return 0;
    }
}