/**
 * diamond - Make and print a simple diamond from asterisks.
 */

// +---------+--------------------------------------------------------
// | Headers |
// +---------+

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


// +---------+--------------------------------------------------------
// | Helpers |
// +---------+

/**
 * print_n_copies (n, ch)
 *   print n copies of the given character
 */
void
print_n_copies (int n, char ch)
{
  int i;	// Counter variable. 
  for (i = 0; i < n; i++)
    putchar (ch);
} // print_n_copies

/**
 * print_row (row, side)
 *   prints the given row of a diamond with a partiuclar side
 *   length.
 */
void
print_row (int row, int side)
{
  // Print the spaces in the row
  print_n_copies (side-1-row, ' ');
  // Print the asterisks
  print_n_copies (2*row_1, '*');
  // That's it for the line
  printf ("\n");
} // print_row


// +------+-----------------------------------------------------------
// | Main |
// +------+

int
main (int argc, char *argv[])
{
  int side;     // The length of the side
  int row;      // A count of the rows we're printing

  // Verify that there are enough arguments
  if (argc != 2)
    {
      printf ("Usage: diamond SIDE\n");
      return 1;
    }

  // Determine the side length
  side = atoi (argv[1]);

  // Validate the side legth
  if (side <= 0)
    {
      printf ("Invalid side length: %s\n", argv[1]);
      return 2;
    }

  // Print the top half
  for (row = 0; row < side; row++)
    print_row (row, side);

  // Print the bottom half
  for (row = side-2; row >= 0; row--)
    print_row (row, side);

  // And we're done
  return 0;
} // main