p_forward.LST 508 B

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  1. Listing:
  2. 1 MODULE PFwd;
  3. 2 VAR ExitCode : INTEGER;
  4. 3 PROCEDURE Even(n : INTEGER) : BOOLEAN;
  5. 4 FORWARD;
  6. 5 PROCEDURE Odd(n : INTEGER) : BOOLEAN;
  7. 6 BEGIN
  8. 7 IF n = 0 THEN RETURN FALSE ELSE RETURN Even(n - 1) END
  9. 8 END Odd;
  10. 9 PROCEDURE Even(n : INTEGER) : BOOLEAN;
  11. 10 BEGIN
  12. 11 IF n = 0 THEN RETURN TRUE ELSE RETURN Odd(n - 1) END
  13. 12 END Even;
  14. 13 BEGIN
  15. 14 IF Even(10) THEN ExitCode := 1 ELSE ExitCode := 0 END
  16. 15 END PFwd.
  17. 0 errors