/* Programs 5-3 and 5-4

   Examples of: 'for' loop, screen input, editing */

main ()
 {

  int i, n, tri_num;

  printf ("How many triangular numbers do you wish to calculate?\n");
  scanf ("%d", &n);
  printf ("\n\nTABLE OF TRIANGULAR NUMBERS\n\n");
  printf ("   n    Sum from 1 to n\n");
  printf ("  ---   ---------------\n");

  tri_num = 0;

  for ( i = 1; i <= n; ++i)
   {
    tri_num = tri_num + i;
    printf ("%4d%13d\n", i, tri_num);
   }
 }


/* Program Output

How many triangular numbers do you wish to calculate?
5

TABLE OF TRIANGULAR NUMBERS

   n    Sum from 1 to n
  ---   ---------------
   1            1
   2            3
   3            6
   4           10
   5           15

*/