# Object-Oriented Programming

> Cambridge Assessment International Education (CAIE) Pseudocode Reference Guide
> Applicable Syllabus: **A Level**

Cambridge A Level (9618) OOP: CLASS declarations, constructor NEW, PUBLIC/PRIVATE encapsulation, inheritance with INHERITS, and SUPER dispatch.

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Classes are defined with `CLASS..ENDCLASS`. Properties and methods default to `PUBLIC` unless marked `PRIVATE`. Constructors use `NEW`. Inheritance uses `INHERITS` and parent methods are chained with `SUPER`.

### Class Definition & Constructor

```pseudocode
// runnable
// Pet class demo
CLASS Pet
   PRIVATE Name : STRING

   PUBLIC PROCEDURE NEW(GivenName : STRING)
      Name <- GivenName
   ENDPROCEDURE
ENDCLASS

// Creating an object
DECLARE MyPet : Pet
MyPet <- NEW Pet("Buddy")
```

### Inheritance & SUPER Dispatch

```pseudocode
CLASS Cat INHERITS Pet
   PRIVATE Breed : STRING

   PUBLIC PROCEDURE NEW(GivenName : STRING,
                        GivenBreed : STRING)
      SUPER.NEW(GivenName)
      Breed <- GivenBreed
   ENDPROCEDURE
ENDCLASS

MyCat <- NEW Cat("Kitty", "Shorthaired")
```

### Encapsulation, Methods & Property Access

```pseudocode
// PUBLIC and PRIVATE visibility
PRIVATE Attempts : INTEGER
Attempts <- 3

PUBLIC PROCEDURE SetAttempts(Number : INTEGER)
   Attempts <- Number
ENDPROCEDURE

PRIVATE FUNCTION GetAttempts() RETURNS INTEGER
   RETURN Attempts
ENDFUNCTION

// Calling methods via dot notation
Player.SetAttempts(5)
OUTPUT Player.GetAttempts()
```


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