DEFINE VARIABLE charArray AS CHARACTER EXTENT 3 INITIAL ["A","B","C"].
DEFINE VARIABLE sizeofArray AS INTEGER.

sizeOfArray = EXTENT(charArray).

RUN GetPermutations(1).

PROCEDURE GetPermutations:
    DEFINE INPUT PARAMETER n AS INTEGER.

    DEFINE VARIABLE i AS INTEGER.
    DEFINE VARIABLE j AS INTEGER.
    DEFINE VARIABLE currentPermutation AS CHARACTER.

    REPEAT i = n TO sizeOfArray:
        RUN swapValues(i,n).
        RUN GetPermutations(n + 1).
        RUN swapValues(i,n).
    END.
    IF n = sizeOfArray THEN DO:
        DO j = 1 TO EXTENT(charArray):
            currentPermutation = currentPermutation + charArray[j].
        END.
        DISPLAY currentPermutation WITH FRAME A DOWN.
    END.
END PROCEDURE.

PROCEDURE swapValues:
    DEFINE INPUT PARAMETER a AS INTEGER.
    DEFINE INPUT PARAMETER b AS INTEGER.
    DEFINE VARIABLE temp AS CHARACTER.
    temp = charArray[a].
    charArray[a] = charArray[b].
    charArray[b] = temp.
END PROCEDURE.