// reads an array length and char array and determines if it is a palindrome
// CS1711 class, 197 November 7

#include<iostream.h>
#include<stdlib.h>

const int MAXPAL=50; //maximum array size for the palindrome

void fill_array(char a[], int a_size, int& a_used);
// fills a character array of size a_size with a_used entries
// based on a function from the text

int palcheck(const char a[], int asize, int alength);
/* a is a character array of size asize with alength items filled
   return 1 if a contains a palindrome, else 0 */

void out_char_arr(char a[], int asize, int alength);
/* a is a character array of size asize with alength items filled
   the array is sent to the output stream */

main()
{ int  pal_len,count = 0;
  char pal[MAXPAL];

 cout << "What is the length of your palindrome?\n";
 cin >> pal_len;
 while ((pal_len > MAXPAL)||(pal_len < 0)) //error trap
  { if (count > 3)
          {cout << "Too many bad inputs, exiting now..."; exit (1);}
	 else
	   {count++;
		cout << "Too long or short, try again...\n";
		 cin >> pal_len;};}; //while
 fill_array(pal,MAXPAL,pal_len);

 cout << "\n\n The string of characters: \n";
 out_char_arr(pal,MAXPAL,pal_len);

 if (palcheck(pal,MAXPAL,pal_len))
   cout << "\n The string is a palindrome";
 else
   cout << "\n The string is a not a palindrome";
 return 0;

}

void fill_array(char a[], int size, int& number_used)
{
	int index = 0;
	char next;

	cout << "Type in the appropriate number of letters\n";

                do {  // while index
		   cin >> next;
		   a[index] = next;
		   index++;
                   }
		while  (index < number_used);

	number_used = index;
}

int palcheck(const char a[], int asize, int alength)
{ const int TRUE=1, FALSE=0;
  int front, back, found;

  front=0;
  back=alength-1;
  found=TRUE;
  while((front<back) && found)
   { if (a[front] != a[back])
	  found=FALSE;
	else
		  {front++;back--;};}
  return found;

}


void out_char_arr(char a[], int asize, int alength)
{ int index=0;

  do {
	cout << a[index];
	index++;}
  while(index < alength);
  cout << endl<<endl;
}