Maze generator

Today, no business topic but it’s play time 🙂 A couple of days ago, I stumbled upon the free book “10 PRINT CHR$(205.5+RND(1)); : GOTO 10“. No joke, that’s the title of the book. It’s about an one-line Commodore 64 BASIC program that prints a maze to the screen. Because I’m a big fan of Retrocomputing, I browsed the book a little bit.

Afterwards I asked myself what ABAP report I could write in one line of 40 characters with a nice output. The answer was sobering: Nothing interesting. Even with 80 characters I just printed vertical lines to the screen 🙂 Here is my approach.

REPORT z.DO 10 TIMES.DO 80 TIMES.WRITE AT sy-index(1) '|'.ENDDO.NEW-LINE.ENDDO.

Finally I decided to give up the length restriction and wrote my own random maze generator as a homage to the original BASIC program. It uses the WRITE instruction and the characters “-” and “|” to build frames. You will find it on GitHub, too.

REPORT z_random_maze.

DATA: lr_random_int TYPE REF TO cl_abap_random_int,
      lv_random_int TYPE i,
      lv_position_x TYPE i,
      lv_position_y TYPE i,
      lv_maze_part  TYPE char2.

lr_random_int = cl_abap_random_int=>create( seed = CONV i( sy-uzeit ) min = 1 max = 9 ).

DO 20 TIMES.
  lv_position_y = sy-index.
  lv_position_x = 1.
  DO 30 TIMES.
    CLEAR lv_maze_part.
    IF lv_position_y = 20.
      lv_maze_part = '--'.
    ELSE.
      lv_random_int = lr_random_int->get_next( ).
      IF lv_random_int < 5.
        lv_maze_part = '|'.
      ELSEIF lv_random_int > 7.
        lv_maze_part = '--'.
      ENDIF.
    ENDIF.
    WRITE AT lv_position_x(2) lv_maze_part.
    lv_position_x = lv_position_x + 2.
  ENDDO.
  NEW-LINE.
ENDDO.

Relax your eyes, try to find your way through the maze and have fun 🙂 Here is a little example of the report output. And if you have a good idea for an interesting one-liner in ABAP, let me know.