HDU2562 奇偶位互换

#include<cmath>
#include<cstdio>
#include<cstring>
#include<iostream>
#include<algorithm>
using namespace std;
int main(void)
{
    int t;
    scanf("%d",&t);
    while(t--)
    {
        char s[100];
        scanf("%s",s);
        char ch;
        for(int i = 0; i < strlen(s); i=i+2)
        {
            ch = s[i];
            s[i] = s[i+1];
            s[i+1] = ch;
        }
        printf("%s\n",s);
    }
    return 0;
}