这个代码为什么运行不了？

Question

输入一串字符，字符个数不超过100，且以“.“结束。判断它们是否构成回文。

#include <iostream>
using namespace std;
int main()
{
    char ch, letter[101];
    cout << "Input a string:";
    cin >> ch;
    int i = 0, j = 1;
    while (ch != ".") {
        ++i;
        letter[i] = ch;
        cin >> ch;
    }
    whlie ((j < i) && (letter[j] == letter[i])) {
        --j; ++i;
    }
    if (j >= i)
        cout << "Yes" << endl;
    else
        cout << "No" << endl;
    return 0;
}

Answer 1

1、第二个while写错了
2、结合上面两位的回答：--j;++i改为++j;--i ch!="."改为ch!='.'

代码如下：
#include
using namespace std;
int main()
{
char ch, letter[101];
cout << "Input a string:";
cin >> ch;
int i = 0, j = 1;
while (ch != '.') {
++i;
letter[i] = ch;
cin >> ch;
}
while((j < i) && (letter[j] == letter[i])) {
++j; --i;
}
if (j >= i)
cout << "Yes" << endl;
else
cout << "No" << endl;
return 0;
}