Compile-time polymorphism in Java - Mini Project: Build & Apply

Compile-time Polymorphism in Java

📖 Scenario: Imagine you are creating a simple calculator program that can add numbers. Sometimes you want to add two numbers, and other times you want to add three numbers. Using compile-time polymorphism, you can create methods with the same name but different numbers of inputs.

🎯 Goal: Build a Java class called Calculator that demonstrates compile-time polymorphism by having two add methods: one that adds two integers and another that adds three integers.

📋 What You'll Learn

Create a class named Calculator.

Inside Calculator, create a method add that takes two int parameters and returns their sum.

Inside Calculator, create another method add that takes three int parameters and returns their sum.

In the main method, create an object of Calculator and call both add methods with appropriate arguments.

Print the results of both method calls.

💡 Why This Matters

🌍 Real World

Compile-time polymorphism is used in many software applications to simplify code and improve readability by using the same method name for similar actions with different inputs.

💼 Career

Understanding method overloading is essential for Java developers as it is a fundamental concept used in designing flexible and reusable code.

1

Create the Calculator class with the main method

Create a public class called Calculator and add a public static void main(String[] args) method inside it.

Java

public class Calculator {
    public static void main(String[] args) {
        // Your code here
    }
}

Need a hint?

Start by writing public class Calculator { and then add the main method inside.

2

Add the first add method with two parameters

Inside the Calculator class but outside the main method, create a public method called add that takes two int parameters named a and b and returns their sum as an int.

Java

public class Calculator {
    public static void main(String[] args) {
        
    }

    // Your code here
}

Need a hint?

Write a method with signature public int add(int a, int b) and return a + b.

3

Add the second add method with three parameters

Inside the Calculator class but outside the main method, create another public method called add that takes three int parameters named a, b, and c and returns their sum as an int.

Java

public class Calculator {
    public static void main(String[] args) {
        
    }

    public int add(int a, int b) {
        return a + b;
    }

    // Your code here
}

Need a hint?

Create a method public int add(int a, int b, int c) that returns a + b + c.

4

Use both add methods and print the results

Inside the main method, create an object of Calculator named calc. Then call calc.add(5, 10) and store the result in an int variable named sumTwo. Next, call calc.add(3, 4, 5) and store the result in an int variable named sumThree. Finally, print both sumTwo and sumThree using System.out.println.

Java

public class Calculator {
    public static void main(String[] args) {
        // Your code here
    }

    public int add(int a, int b) {
        return a + b;
    }

    public int add(int a, int b, int c) {
        return a + b + c;
    }
}

Need a hint?

Create an object with new Calculator(), call both add methods, and print the results.