判断是否是回文数

/*回文数判断*/
#include <iostream>
#include <string>
using namespace std;

int main()
{
	string str;
	cin >> str;

	int backward = 0;
	int farward = str.size() - 1;

	for ( ; backward <= farward; backward++, farward--) {
		if (str[backward] != str[farward]) {
			break;
		}
	}

	if (backward > farward) {
		cout << "是回文数";
	} else {
		cout << "不是回文数";
	}


}