/* 

  Stair case in Picat.

  Ported from B-Prolog program
  http://www.probp.com/examples/foreach/staircase.pl
  """
  Draw a staircase of a given steps. Example query:

  ?-go(4).
              +---+
              |   |
          +---+---+
          |   |   |
      +---+---+---+
      |   |   |   |
  +---+---+---+---+
  |   |   |   |   |
  +---+---+---+---+   
  """

  This Picat model was created by Hakan Kjellerstrand, hakank@gmail.com
  See also my Picat page: http://www.hakank.org/picat/

*/


% import util.
% import cp.


main => go.

go =>
    go(4).

go(N) => 
    foreach(I in 1..N)
	foreach(J in 1..N-I) print("    ") end,
	foreach(J in 1..I)  print("+---") end,
	println("+"),
	foreach(J in 1..N-I)  print("    ") end,
	foreach(J in 1..I)  print("|   ") end,
	println("|")
    end,
    foreach(I in 1..N) print("+---") end, println("+").