反转字符串,异或运算符:

#include<iostream>
#include<string>
using namespace std;
string reverse(string a)
{
    int n=a.length();
    for(int i=0; i<n/2; i++){
        a[i]^=a[n-i-1];
        a[n-i-1]^=a[i];
        a[i]^=a[n-i-1];
    }
    return a;
}
int main()
{
    string s;
    getline(cin, s);
    cout<<reverse(s)<<endl;
    return 0;
}