#include <iostream>
#include<string>
using namespace std;
bool f(string str)
{
int strlen = str.length();
bool flag = true;
if (strlen <= 1)
return true;
for (int i = 0; i < strlen / 2; i++)
{
if (str[i] != str[strlen - 1 - i])
flag = false;
break;
}
return flag;
}
int main() {
string a("abc");
string b("abba");
if (f(a))
cout << "是回文字符串" << endl;
else
cout << "不是回文字符串" << endl;
if (f(b))
cout << "是回文字符串" << endl;
else
cout << "不是回文字符串" << endl;
return 0;
}