C++算法代码——判断回文

#include <bits/stdc++.h>
using namespace std;

int main(){
    char a[101],k;
    int len = 0;
    while (true){
        cin >> k;
        if (k != ‘.‘) a[len] = k;
        else break;
        len++;
    }
    if (len % 2 == 0){
        for (int i = 0;i < len / 2;i++){
            if (a[i] != a[len - i - 1]){
                cout << "no";
                return 0;
            }
        }
        cout << "yes";
    }
    else{
        for (int i = 0;i <= len / 2;i++){
            if (a[i] != a[len - i - 1]){
                cout << "no";
                return 0;
            }
        }
        cout << "yes";
    }
    return 0;
}