# include <stdio.h>

//
//  Program 5.4, Stephen Kochan, Programming in C.
//

int main ( void )
{
  int n, number, triangularNumber;

  printf ( "What triangular number do you want?  " );
  scanf ( "%i", &number );

  triangularNumber = 0;

  for ( n = 1; n <= number; n = n + 1 )
  {
    triangularNumber = triangularNumber + n;
  }

  printf ( "The %ith triangular number is %i.\n", number, triangularNumber );

  return 0;
}