Use note passing for explaining the difference between methods with no return (void methods) and methods with return to provide students with a relatable example.

  • Have students think about two different types of notes, Notes That Make A Statement and Notes That Ask A Question, and how they are supposed to respond to each to help them understand the difference between void methods and methods that return something.
    • Notes That Make A Statement - Notes that makes a statement do not need an answer.
      • This type of note tells information to the receiver and the receiver does what they need to do with it.
      • This note is never handed back.
    • Notes That Ask A Question - A note that asks a question gets read by the person receiving it, then they write down an answer, then the answer is returned.
      • This type of note gets handed back.
      • The only way a return is worth anything is if the returned information is processed by the calling location (place asking the question).
      • This means that you need to use the returned information.
        • This means saving this information (as a variable) a lot of the time.
    • Use the following example code to finish illustrating this point:
      • public void methodCall()   : Place where Note That Makes A Statement is received.
      • methodCall();   : This is "passing" the Note That Makes A Statement.
      • public String method2()   : Place where the Note That Asks A Question is received and where the answer is written back.
      • String variable = method2();   : Place "passing" the Note That Asks A Question and saving the answer in a variable, variable.
        • Right side is "passing" the note with the question.
        • Left side is grabbing the notecard with the answer on it back and reading/saving it.
          • If you don’t grab the card and read/save it, all the work of passing the note and answering it went to waste.

More about this tip

External Source

Interview with Dani McAvoy