COBOL program to find the factorial

Main Program (FACT.COB)

       IDENTIFICATION DIVISION.

       PROGRAM-ID. FACT.

       ENVIRONMENT DIVISION.

       DATA DIVISION.

       WORKING-STORAGE SECTION.

       77 N PIC 9(2).

       77 FACT PIC 9(6).

       77 RESULT PIC Z(5)9.

       PROCEDURE DIVISION.

       P1.

           DISPLAY "ENTER NUMBER TO FIND FACTORIAL".

           ACCEPT N.

           IF N = 0

              MOVE 0 TO RESULT

           ELSE

              CALL "F.COB" USING N, FACT.

           MOVE FACT TO RESULT.

           DISPLAY "FACTORIAL OF " N " IS: " , RESULT.

           STOP RUN.

F.COB FILE 

Sub Program (Subroutine called from main program)

       IDENTIFICATION DIVISION.

       PROGRAM-ID.

       ENVIRONMENT DIVISION.

       DATA DIVISION.

       WORKING-STORAGE SECTION.

       77 Z PIC 9(2).

       LINKAGE SECTION.

       77 N PIC 9(2).

       77 FACT PIC 9(6).

       PROCEDURE DIVISION USING N FACT.

       P1.

           MOVE 1 TO FACT.

           PERFORM COMPUTE-PARA VARYING Z FROM 2 BY 1 UNTIL Z > N.

           EXIT PROGRAM.

       COMPUTE-PARA.

           MULTIPLY Z BY FACT.