begin comment LIBRARY 1; integer I; switch S ≔ S1, S2, S3, S4; for I ≔ 1 step 1 until 4 do begin goto S[I]; S1 :; if I ≠ 1 then OUTREAL(99, I) else goto EXIT; S2 :; if I ≠ 2 then OUTREAL(99, I) else goto EXIT; S3 :; if I ≠ 3 then OUTREAL(99, I) else goto EXIT; S4 :; if I ≠ 4 then OUTREAL(99, I) else goto EXIT; EXIT :; end; end