reverse

#include <stdio.h>
#include <cs50.h>
#include <string.h>
#include <ctype.h>

#define MAX 100
int top;

/*PUSH FUNCTION*/
void push (char stack[], char* item)
{
    ++top;
    stack [top] = *item;
}

char pop (char stack[])
{
    char ret;
    if (top == -1)
    {
        ret = 0;
    }
    else
    {
        ret = stack [top];
        --top;
    }
return ret;
}

int main(void)
{
    //char stack[MAX];
    char word[MAX];
    top = -1;
    string s = GetString();
    int len = strlen(s);

    int x = 1;
    if (len < 0 || len > MAX)
    {
        return 1;
    }
    for(int i = 0, j = 0; i <= len; i++)
    {
        if (!isalnum(s[i]))
        {
            while (x <= j)
            {
                s[x] = pop(word);
                printf("%c", s[x]);
                x++;
            }
            x = 0;
            j = 0;
        }
        else
        {
            push(word, &s[i]);
            j++;
        }

    }

}