PROGRAM JOSEPHUS

!
! for rosettacode.org
!

!$INTEGER

DIM DEAD[100]

PROCEDURE MAIN(N,K,S->ERRORS)
! n - number of prisoners
! k - kill every k'th prisoner
! s - number of survivors
    LOCAL KILLED$,SURVIVED$,FOUND,P,NN,I
    ERRORS=0
    FOR I=0 TO 100 DO
        DEAD[I]=0
    END FOR   ! prepare array
    PRINT("N=";N,"K=";K,"S=";S)        ! show arguments
    IF S>N THEN PRINT("S>N";) ERRORS+=1 END IF
    IF K<=0 THEN PRINT("K<=0";) ERRORS+=1 END IF
    IF ERRORS>0 THEN EXIT PROCEDURE END IF
    NN=N                               ! wrap around boundary
    P=-1                               ! start here
    WHILE N<>S DO                      ! until survivor count is met
      FOUND=0                          ! start looking
      WHILE FOUND<>K DO                ! until we have the k-th prisoner
        P+=1
        IF P=NN THEN P=0 END IF        ! wrap around
        IF DEAD[P]<>1 THEN
            FOUND+=1
        END IF                         ! if prisoner is alive increment found
      END WHILE
      DEAD[P]=1                        ! kill the unlucky one
      KILLED$=KILLED$+STR$(P)          ! build killed list
      N-=1                             ! reduce size of circle
    END WHILE
    FOR I=0 TO NN-1 DO
      IF DEAD[I]<>1 THEN
        SURVIVED$=SURVIVED$+STR$(I)    ! build survivor list
      END IF
    END FOR
    PRINT("Killed:";KILLED$)
    PRINT("Survived:";SURVIVED$)
END PROCEDURE

BEGIN
    ERRORS=0
    MAIN(5,2,1->ERRORS)
    MAIN(41,3,1->ERRORS)
    MAIN(41,3,3->ERRORS)
END PROGRAM