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

int string_length(char * my_string);
char * reverse_string(char * my_string);


int strings_equal(char * string1, char * string2)
{
  int length1 = string_length(string1);
  int length2 = string_length(string2);
  if (length1 != length2)
  {
    return 0;
  }

  int i;
  for (i = 0; i < length1; i++)
  {
    if (string1[i] != string2[i])
    {
      return 0;
    }
  }

  return 1;
}

// returns 1 if the string is a palindrome, 0 otherwise.
int is_palindrome(char * my_string)
{
  int result;
  char * reverse = reverse_string(my_string);
  if (strings_equal(reverse, my_string) == 1)
  {
    result = 1;
  }
  else
  {
    result = 0;
  }

  free(reverse);
  return result;
}


int string_length(char * my_string)
{
  int counter = 0;
  while(1)
  {
    if (my_string[counter] != 0)
    {
      counter++;
    }
    else
    {
      break;
    }
  }

  return counter;
}



char * reverse_string(char * my_string)
{
  int length = string_length(my_string);
  char * result = (char *) malloc(sizeof(char) * (length + 1));

  int i;
  for (i = 0; i < length; i++)
  {
    int j = length - i - 1;
    result[i] = my_string[j];
  }

  result[length] = 0;
  return result;
}

int main()
{
  char * input = (char *) malloc(sizeof(char) * 1000);
  printf("enter a string:\n");
  scanf("%s", input); 

  int result = is_palindrome(input);
  if (result == 1)
  {
    printf("%s IS a palindrome!!!\n");
  }
  else
  {
    printf("%s is NOT a palindrome\n");
  }

  free(input);
}