TypeCobolFunctionNutshell

Functions and procedure in a Nutshell

Simple example

identification division.
program-id. MyProgram.
data division.
working-storage section.
01  myDate1 TYPE Date.
01  myDate2 TYPE Date.
01  numberOfDays pic 9(05) comp-5.

procedure division.

*Procedure to calculate the number of days between 2 dates
declare procedure daysBetween private
                       input   date1 type Date
                               date2 type Date
                       output  nbOfDays pic 9(05) comp-5.
procedure division.
*   The details of the calcul is not detailled here...
    move result to nbOfDays
    .
end-declare.

 
*Call your procedure
    call daysBetween input  myDate1
                            myDate2
                     output numberOfDays
    goback
    .
 end program MyProgram. 

Advantages of function/procedure

By comparison against a standard Cobol 85 program/nested program

• Syntax shorter than a nested program or a program

• Name your function with more than 8 characters

• Specify your input/output parameters

• Control your arguments (input/output) at compilation time

  • control the number of arguments and their types

  • control the size of parameters (2017)

• Propose visibility mechanism (private and public)

• Have the return code as an implicit parameter (2017)

• Check if caller test the return code (2017)

• Function chaining (2017/2018)