回文是指正读反读均相同的字符序列，如“abb a”和“abdba”均是回文，但“good”不是回文。试写一个链栈c语言算法判定给定的字符向量是否为回文。（提示：将一半字符入栈)

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

#define MAX_SIZE 100

typedef struct Node{
    char data;
    struct Node *next;
}Node, *Stack;

Stack createStack(){
    Stack s = (Stack)malloc(sizeof(Node));
    s->next = NULL;
    return s;
}

int isEmpty(Stack s){
    return s->next == NULL;
}

void push(Stack s, char data){
    Node *new_node = (Node*)malloc(sizeof(Node));
    new_node->data = data;
    new_node->next = s->next;
    s->next = new_node;
}

char pop(Stack s){
    if(isEmpty(s)){
        printf("Stack is empty!\n");
        exit(1);
    }
    Node *p = s->next;
    s->next = p->next;
    char data = p->data;
    free(p);
    return data;
}

int palindrome(char *str){
    Stack s = createStack();
    int len = strlen(str);
    int mid = len / 2;
    int i;
    for(i = 0; i < mid; i++){
        push(s, str[i]);
    }
    if(len % 2 == 1) i++;
    while(str[i] != '\0'){
        if(str[i] != pop(s)){
            return 0;
        }
        i++;
    }
    return 1;
}

int main(){
    char str[MAX_SIZE];
    printf("Enter a string: ");
    fgets(str, MAX_SIZE, stdin);
    str[strlen(str)-1] = '\0'; //去掉fgets读入的换行符
    if(palindrome(str)){
        printf("%s is a palindrome.\n", str);
    }else{
        printf("%s is not a palindrome.\n", str);
    }
    return 0;
}