A-LevelComputer ScienceData types and structures9618/32 · May/June 2022 · Q19 Marks

Data types can be defined using pseudocode. The data type, BuildingRecord, is defined in pseudocode as: TYPE BuildingRecord DECLARE BuildingID : INTEGER DECLARE BuildingGroup : STRING DECLARE OwnerName : STRING DECLARE BuildingAddress : STRING DECLARE DateLastSold : DATE DECLARE PriceLastSold : REAL ENDTYPE A variable, BuildingRegister, is declared in pseudocode as: DECLARE BuildingRegister : BuildingRecord

(a)Write pseudocode statements to assign: • • 1067 to the BuildingID of BuildingRegister house to the BuildingGroup of BuildingRegister[2]
(b)(i)Write the type declaration for BuildingType in pseudocode.[2]
(b)(ii)Write the new declaration for BuildingGroup in pseudocode.[1]
(b)(iii)Write the new pseudocode statement to assign house to BuildingGroup of BuildingRegister.[1]
(c)(i)Write the declaration in pseudocode for OwnerName as PRIVATE.[1]
(c)(ii)Explain why the properties have been set to PRIVATE.[2]

Mark scheme

Marking points from the official mark scheme (May/June 2022). The mark or mark type is shown in brackets.

[2] BuildingRegister.BuildingID ← 1067 BuildingRegister.BuildingGroup ← "house"
[2] One mark: TYPE BuildingType = One mark: (house, bungalow, apartment, farm) TYPE BuildingType = (house, bungalow, apartment, farm)
[1] DECLARE BuildingGroup : BuildingType
[1] BuildingRegister.BuildingGroup ← house
[1] PRIVATE OwnerName : STRING
[2] To ensure that attributes can only be accessed by the class's own methods To enforce encapsulation // ensure they are hidden

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