1. COBOL example

    In my comment on the post Logical flow of an Interactive program the structure of the COBOL source code got lost, here is how it's supposed to look:

           MainParagraph.
               perform InitProgram
               perform ProcessScreen
                 until EndOfProgram
               perform ExitProgram
    
               goback
               .
    
           InitProgram.
               set ContinueProgram             to true
               .
    
           ExitProgram.
               continue
               .
    
           ProcessScreen.
               perform ShowScreen
    
               evaluate true
                 when EnterKey
                   perform CheckInput
    
                 when CF03
                   set EndOfProgram            to true
                   set linkF03Used             to true
    
                 when CF08
                   perform CheckInput
    
                   if NoErrors
                      perform WriteData
                   end-if
    
                   if NoErrors
                      set EndOfProgram         to true
                   end-if
    
                 when CF12
                    set EndOfProgram           to true
                    set linkF12Used            to true
               end-evaluate
               .