csapp::inplace_swap——通过异或实现swapP38

void inplace_swap(int *x,int *y)
{
    *y = *x ^ *y; //step1
    *x = *x ^ *y; //step2
    *y = *x ^ *y; //step3
}

 

 

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

void inplace_swap(int *x,int *y)
{
    *y = *x ^ *y; //step1
    *x = *x ^ *y; //step2
    *y = *x ^ *y; //step3
}

int d_array[10] = {1,2,3,4,5,6,7,8,9,10};
int s_array[9] = {1,2,3,4,5,6,7,8,9};

void reverse_array(int a[],int sz)
{
    for(int i = 0, j = sz - 1; i < j; i++,j--) //不可i<=j因为当sz为奇数时会导致中间值为0
        inplace_swap(&a[i],&a[j]);
}

void show(int a[],int sz)
{
    for(int i = 0; i < sz; ++i)
        printf("%d ",a[i]);
    puts("");
}

int main()
{
    reverse_array(d_array,10);
    reverse_array(s_array,9);
    show(d_array,10);
    show(s_array,9);
}