C语言函数实现两个数的交换、指针操作

用函数实现数的交换

#include<stdio.h>

void swap(int x,int y)			//这个时候传递的就是值
{
    int t;
    t = x;
    x = y;
    y = t;				//值交换
    printf("a = %d
",x);
    printf("b = %d
",y);
}

int main()
{
    int a = 1,b = 2;
    swap(a,b);			//改变的是形参，但是实参没有改变
    printf("a = %d
",a);
    printf("b = %d
",b);
    return 0;
}

得到结果：

#include<stdio.h>

void swap(int *x,int *y)			//这个时候交换的是地址
{
    int *t;
    printf("a = %d
",x);
    printf("b = %d
",y);
    t = x;
    x = y;
    y = t;
    printf("a = %d
",x);
    printf("b = %d
",y);			//前后的地址交换了
}

int main()
{
    int a = 1,b = 2;
    swap(&a,&b);
    printf("a = %d
",a);
    printf("b = %d
",b);
    return 0;
}

#include<stdio.h>

void swap(int *x,int *y)				//按指针传递
{
    int t;
    t = *x;
    *x = *y;
    *y = t;				//此时交换的时指针指向的值
    printf("a = %d
",*x);
    printf("b = %d
",*y);
}

int main()
{
    int a = 1,b = 2;
    swap(&a,&b);			
    printf("a = %d
",a);
    printf("b = %d
",b);
    return 0;
}