用C写一个判断字符串是否是回文的代码，用栈来实现。

#include <stdio.h>
#include <string.h>

#define MAX_SIZE 100

int top = -1;
char stack[MAX_SIZE];

void push(char c)
{
if (top == MAX_SIZE - 1)
{
printf("Stack Overflow\n");
}
else
{
top++;
stack[top] = c;
}
}

char pop()
{
if (top == -1)
{
printf("Stack Underflow\n");
return -1;
}
else
{
char c = stack[top];
top--;
return c;
}
}

int isPalindrome(char str[])
{
int len = strlen(str);
int i;
for (i = 0; i < len/2; i++)
{
push(str[i]);
}
if (len % 2 != 0)
{
i++;
}
while (str[i] != '\0')
{
char c = pop();
if (c != str[i])
{
return 0;
}
i++;
}
return 1;
}

int main()
{
char str[MAX_SIZE];
printf("Enter a string: ");
scanf("%s", str);
if (isPalindrome(str))
{
printf("%s is a palindrome\n", str);
}
else
{
printf("%s is not a palindrome\n", str);
}
return 0;
}