Functions

A function returns one value

• A function is like a procedure, and it also hands one value back.
• The definition says the type of that value: RETURNS INTEGER.
• RETURN sets the value. It is normally the last line of the function.

FUNCTION Square(Number : INTEGER) RETURNS INTEGER
  RETURN Number * Number
ENDFUNCTION
OUTPUT Square(6)

Do not write CALL

• A function is used inside an expression, where its returned value is needed.
• CALL is only for a procedure.
• Parameters of a function are passed by value. The guide says not to use BYREF on a function.

FUNCTION Max(Number1 : INTEGER, Number2 : INTEGER) RETURNS INTEGER
  IF Number1 > Number2 THEN
    RETURN Number1
  ELSE
    RETURN Number2
  ENDIF
ENDFUNCTION
OUTPUT Max(10, 24)

Common mistakes

A definition does not display a result by itself. Trace a call such as OUTPUT Max(4, 7): the function returns once, and the caller outputs once. An extra output inside the function changes the required output.

• RETURN belongs inside the function. Outside it, there is nothing to return to.
• The call Square(6) is not a complete statement on its own. OUTPUT Square(6) is.

Now you try

• Write a function and use its result in OUTPUT.

Independent transfer

The final task has no supplied algorithm. Plan its inputs, processing and outputs, then solve it before opening support. Check more than the sample case.