栈（回文数）

#include <stdio.h>#include <string.h>int main(){    int len,i,top,next,mid;    char c[100],s[100];    gets(c);    len = strlen(c);    mid = len/2 - 1;    top = 0;    for(i = 0;i <= mid;i++)        s[++top] = c[i];    if(len%2 == 0)        next = mid + 1;    else        next = mid + 2;    for(i = next;i <= len-1;i++)    {        if(s[top] != c[i])            break;        top--;    }    if(top == 0)        printf("YES\n");    else        printf("NO\n")  ;    return 0;}