文章内容

C: (memory) 通用的交换数据方法

发布时间: 2012/9/9 11:01:22

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

void intSwap (int *a, int *b)
{
    int temp = *a;
    *a = *b;
    *b = temp;
}

void genericSwap (void *a, void *b, size_t size)
{
    void *temp = malloc(size);
    memcpy(temp, a, size);
    memcpy(a, b, size);
    memcpy(b, temp, size);
}


int main(int argc, const char * argv[])
{
    // swap two integers
    int m = 1;
    int n = 2;
    intSwap(&m, &n);
    printf("%d,%d\n", m, n); // 2,1

    // generic swap (int test)
    int j = 3;
    int i = 4;
    genericSwap(&j, &i, sizeof(int));
    printf("%d,%d\n", j, i); // 4,3

    // generic swap (struct test)
    typedef struct {
        int height;
        int weight;
    } human;

    human tom;
    tom.height = 188;
    tom.weight = 85;

    human jerry;
    jerry.height = 190;
    jerry.weight = 99;

    genericSwap(&tom, &jerry, sizeof(human));
    printf("tom: %d, %d jerry: %d, %d\n",
           tom.height, tom.weight,
           jerry.height, jerry.weight);
    //tom: 190, 99 jerry: 188, 85

    return 0;
}