Records

Different types under one name

• AS topic 10.1 asks you to define a record: one identifier holding fields of different types.
• TYPE … ENDTYPE names the record and declares each field.
• This is not an A2 class. There are no methods here.

TYPE Student
  DECLARE Name : STRING
  DECLARE Mark : INTEGER
ENDTYPE
DECLARE S : Student
S.Name ← "Ada"
S.Mark ← 91
OUTPUT S.Name & " " & S.Mark

A field is read with a dot

• S.Name is the Name field of S.
• You may copy a whole record: Pupil2 ← Pupil1 copies every field.
• An array of records uses one index, then the field: Form[1].Mark.

TYPE Student
  DECLARE Name : STRING
  DECLARE Mark : INTEGER
ENDTYPE
DECLARE Form : ARRAY[1:2] OF Student
Form[1].Name ← "Ada"
Form[1].Mark ← 91
Form[2].Name ← "Bo"
Form[2].Mark ← 80
OUTPUT Form[2].Name

Watch out

• Declare the TYPE before you DECLARE a variable of that type.
• Enumerated types and pointers are A2 (topic 13.1). They are not in this AS course.

Common mistakes

• Each field has its own DECLARE inside the TYPE.
• ENDTYPE closes the definition. Forgetting it leaves the type unfinished.

Now you try

• Define a record, store two fields, and output them.