Programming Inheritance (OCR A Level Computer Science): Revision Note

Programming Inheritance

• To program inheritance, you should already have a solid understanding of what inheritance in Object Oriented Programming (OOP) is.

How do you Define Inheritance?

Pseudocode

Pseudocode for a class created using inheritance

Java

//vehicle class created

public class Vehicle {

       //attributes created for the vehicle class

    private String manufacturer;

    private String make;

    private double cost;

    //constructor to create objects of type vehicle

    public Vehicle(String manufacturer, String make, double cost) {

        this.manufacturer = manufacturer;

        this.make = make;

        this.cost = cost;

    }

    //method to start the engine of the car

    public void turnEngineOn() {

        //code to turn the engine on

    }

    //method to stop the engine of the car

    public void turnEngineOff() {

        //code to turn the engine off

}

    //method to steer the car to the left

    public void steerLeft() {

        // code to steer the vehicle left

    }

    //method to steer the car to the right

    public void steerRight() {

        // code to steer the vehicle right

    }

}

//Derived Class (Car)

//the Car class uses the keyword 'extends' to inherit from the Vehicle class

public class Car extends Vehicle {

    private boolean isInsured;

    private double engineCapacity;

    // Constructor to create objects of type Car

    public Car(String manufacturer, String make, double cost, boolean isInsured, double   engineCapacity) {

       //the super keyword is used to inherit the attributes from the base class

         super(manufacturer, make, cost);

        this.isInsured = isInsured;

        this.engineCapacity = engineCapacity;

    }

    //method to change gear 

    public void gearChange() {

        //code to change the gear of the car

    }

    //method to unlock the vehicle doors

    public void unlockDoors() {

        //code to unlock the doors of the car

    }

}

Python

#Base class (Vehicle)

#Vehicle class created

class Vehicle:

     #attributes created for the Vehicle class 

   def __init__(self, manufacturer, make, cost):

        self.manufacturer = manufacturer

        self.make = make

        self.cost = cost

     #method to start the engine of the car   

   def turn_engine_on(self):

        # Code to turn the engine on

    #method to stop the engine of the car

    def turn_engine_off(self):

        # Code to turn the engine off

        #method to steer the car to the left

    def steer_left(self):

        # Code to steer the vehicle left

        #method to steer the car to the right

    def steer_right(self):

        # Code to steer the vehicle right

#Derived Class (Car)

#the Car class uses the keyword parent class name in parenthesis to inherit from the Vehicle class

class Car(Vehicle):

    def __init__(self, manufacturer, make, cost, is_insured, engine_capacity):

           #the super keyword is used to inherit the attributes from the base class

        super().__init__(manufacturer, make, cost)

        self.is_insured = is_insured

        self.engine_capacity = engine_capacity

    #method to change gear

    def gear_change(self):

        # Code to change the gear of the car

        #method to steer the car to the right

    def unlock_doors(self):

        # Code to unlock the doors of the car