factorial.cob

       *> Open COBOL -- https://open-cobol.sourceforge.io/
       *> This program computes the factorial of n
       *> Run it in the terminal with these two commands:
       *> 1. $ cobc -x factorial.cob
       *> 2. $ ./factorial

        IDENTIFICATION DIVISION.
        PROGRAM-ID. Factorial.

        DATA DIVISION.
        WORKING-STORAGE SECTION.
        01 n      BINARY-LONG.
        01 i      BINARY-LONG.
        01 prod   BINARY-LONG VALUE 1.

        PROCEDURE DIVISION.
        DISPLAY "Enter a positive integer (e.g. 10)"
        ACCEPT n
        PERFORM VARYING i FROM 1 BY 1 UNTIL i > n
            MULTIPLY prod BY i GIVING prod
        END-PERFORM
        DISPLAY "The factorial of " n " is " prod ".".