college/Summer-2024/CS-3443/Slides/txt/09_Polymorphism.txt

Application
Programming
Hend Alkittawi

OOP Concepts
Polymorphism

POLYMORPHISM
-

Polymorphism enables you to write programs that processes
objects that share the same superclass either directly or
indirectly as if they were all objects of the superclass.

-

The polymorphism occurs when a program invokes a method
through a superclass variable, at execution time the correct
subclass version of the method is called based on the type of
reference stored in the superclass variable.

-

A program can determine the type of an object at execution
time and act on that object accordingly.

POLYMORPHISM

Animal

Fish

🐟

Frog

🐸

Bird

🐦

xy coordinates

xy coordinates

xy coordinates

move()

move()

move()

POLYMORPHISM
Quadrilatera
l

Square

Trapezoid

Parallelogram
s

color

color

color

getPerimeter()

getPerimeter()

getPerimeter()

POLYMORPHISM

SpaceObject

LaserBeam

SpaceShip

Plutonian

picture

picture

picture

draw()

draw()

draw()

public class Animal {

public class PolymorphismDemo {

private String name;

public static void main(String[] args) {

public Animal(String name) { this.name = name; }

// Animal reference but Dog object
Animal myAnimal = new Dog("Thunder", 30);
// Output: Thunder the dog barks.
myAnimal.makeSound();

public String getName() { return name; }
public void setName(String name) { this.name = name; }

// Animal reference but Cat object
myAnimal = new Cat("Whiskers", "Persian");
// Output: Whiskers the cat meows.
myAnimal.makeSound();

public void eat() { System.out.println(getName() + " eats food."); }
public void makeSound() { System.out.println("Animal makes a sound."); }
}

}
}

public class Dog extends Animal {
public class Cat extends Animal {
private int exerciseNeeds; // in min/day
private String breed;
public Dog(String name, int exerciseNeeds) {
super(name);
this.exerciseNeeds = exerciseNeeds;
}
public int getExerciseNeeds() {
return exerciseNeeds;
}
public void setExerciseNeeds(int exerciseNeeds) {
this.exerciseNeeds = exerciseNeeds;
}
@Override
public void makeSound() {
System.out.println(getName() + " the dog barks.");
}
}

public Cat(String name, String breed) {
super(name);
this.breed = breed;
}
public String getBreed() {
return breed;
}
public void setBreed(String breed) {
this.breed = breed; }
@Override
public void makeSound() {
System.out.println(getName() + " the cat meows.");
}
}

CODE DEMO
-

Create classes to demo
polymorphism concepts!

DO YOU HAVE ANY
QUESTIONS?

THANK
YOU!

@

hend.alkittawi@utsa.edu

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