Computer Science
Grade 9
20 min
Polymorphism
Polymorphism
Tutorial Preview
1
Introduction & Learning Objectives
Learning Objectives
Define polymorphism and its role in Object-Oriented Programming.
Differentiate between method overloading and method overriding.
Explain how polymorphism allows for more flexible and reusable code.
Write a simple program that demonstrates method overloading.
Write a simple program that demonstrates method overriding using inheritance.
Identify examples of polymorphism in a given code snippet.
Have you ever used a single '+' button on a calculator to add numbers, but the same '+' symbol in code to join words? How can one symbol have so many different jobs? 🤔
This lesson introduces Polymorphism, a core concept in Object-Oriented Programming. You will learn how objects can take on 'many forms', allowing us to write smarter, mo...
2
Key Concepts & Vocabulary
TermDefinitionExample
PolymorphismFrom Greek, meaning 'many forms'. It's the ability of a method or object to behave in different ways depending on the context or the data it is working with.An `Animal` object can be a `Dog` object or a `Cat` object. Calling the `makeSound()` method on it will result in 'Woof!' for the dog and 'Meow!' for the cat.
Method OverloadingWhen a single class has multiple methods with the same name but different parameters (different number of parameters, or different types of parameters). This is also known as compile-time polymorphism.A `Calculator` class might have `add(int a, int b)` to add two integers and `add(double a, double b)` to add two decimal numbers.
Method OverridingWhen a child class provides its own specific imp...
3
Core Syntax & Patterns
Method Overloading Pattern
class MyClass {
returnType methodName(type1 param1) { ... }
returnType methodName(type1 param1, type2 param2) { ... }
returnType methodName(typeA paramA) { ... }
}
Use this inside a single class when you want one method name to perform similar actions on different types or numbers of inputs. The compiler chooses the correct method to call based on the arguments you provide.
Method Overriding Pattern
class Parent {
void doSomething() { ... }
}
class Child extends Parent {
@Override
void doSomething() { ... } // New implementation
}
Use this in a child class to provide a specialized behavior for a method that is already defined in its parent class. The method signature (name and parameters) must be identical to the parent's method....
4 more steps in this tutorial
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Sign Up Free to ContinueSample Practice Questions
Easy
What is the literal meaning of the word 'polymorphism' as described in the tutorial?
A.Many classes
B.One form
C.Multiple inheritances
D.Many forms
Easy
Which of the following best defines Method Overloading?
A.child class providing a new implementation for a parent class's method.
B.single class having multiple methods with the same name but different parameters.
C.class inheriting properties from another class.
D.method that can take on many forms.
Easy
What is the primary requirement for Method Overriding to occur?
A.Two classes must be unrelated.
B.The methods must have different names.
C.child class must provide its own version of a method from its parent class.
D.The methods must be in the same class.
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