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(N : INTEGER) RETURNS INTEGER
  RETURN N * N
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

• 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.