Ordenamiento por selección

IDENTIFICATION DIVISION.
PROGRAM-ID. ORDENAMIENTO-POR-SELECCION.

DATA DIVISION.
WORKING-STORAGE SECTION.
01 TIMESTAMP.
    02 FILLER   PIC 9(06).
    02 MS       PIC 9(02).

77 TABLA        PIC 9(02) OCCURS 20 INDEXED BY I.
77 AUX          PIC 9(02).
77 J            PIC 9(02).

PROCEDURE DIVISION.
MAIN-PROCEDURE.
    PERFORM RELLENAR-TABLA.
    DISPLAY "TABLA ORIGINAL".
    PERFORM MOSTRAR-TABLA.
    PERFORM ORDENAR-TABLA.
    DISPLAY "TABLA ORDENADA".
    PERFORM MOSTRAR-TABLA.
    STOP RUN.

MOSTRAR-TABLA.
    PERFORM VARYING I FROM 1 BY 1 UNTIL I > 19
        DISPLAY TABLA(I), ", " WITH NO ADVANCING
    END-PERFORM.
    DISPLAY TABLA(I).

RELLENAR-TABLA.
    COMPUTE TABLA(1) = FUNCTION RANDOM(FUNCTION SECONDS-PAST-MIDNIGHT) * 99 + 1.
    PERFORM VARYING I FROM 2 BY 1 UNTIL I > 20
        COMPUTE TABLA(I) = FUNCTION RANDOM * 99 + 1
    END-PERFORM.

ORDENAR-TABLA.
    PERFORM VARYING I FROM 1 BY 1 UNTIL I > 20
        MOVE I TO AUX
        PERFORM VARYING J FROM I BY 1 UNTIL J > 20
            IF TABLA(AUX) > TABLA(J) THEN
                MOVE J TO AUX
            END-IF
        END-PERFORM
        *> REUTILIZACION DE AUX. AQUÍ SE PUEDE. EN OTRO CONTEXTO TAL VEZ SERIA
        *> NECESARIA UNA VARIABLE AUXILIAR
        MOVE AUX TO J
        MOVE TABLA(I) TO AUX
        MOVE TABLA(J) TO TABLA(I)
        MOVE AUX TO TABLA(J)
    END-PERFORM.

END PROGRAM ORDENAMIENTO-POR-SELECCION.