Type promotion in Java - Mini Project: Build & Apply

Type Promotion in Java

📖 Scenario: Imagine you are working on a simple calculator program that adds two numbers. Sometimes these numbers are small, like bytes or shorts, but Java automatically promotes them to a larger type before adding. This project will help you understand how Java promotes smaller types to int during arithmetic operations.

🎯 Goal: You will create two small numbers using byte type, then add them using Java's type promotion rules, and finally print the result.

📋 What You'll Learn

Create two byte variables with exact values 10 and 20

Create an int variable to hold the sum of the two bytes

Add the two byte variables and assign the result to the int variable

Print the sum using System.out.println

💡 Why This Matters

🌍 Real World

Understanding type promotion helps avoid errors when working with small number types in Java, especially in calculations and data processing.

💼 Career

Many Java jobs require knowledge of data types and how arithmetic operations handle them to write efficient and bug-free code.

1

Create two byte variables

Create two byte variables called num1 and num2 with values 10 and 20 respectively.

Java

// Your code here

Need a hint?

Use byte num1 = 10; and byte num2 = 20; inside the main method.

2

Create an int variable for the sum

Create an int variable called sum to hold the result of adding num1 and num2.

Java

public class Main {
    public static void main(String[] args) {
        byte num1 = 10;
        byte num2 = 20;
        // Your code here
    }
}

Need a hint?

Declare int sum; inside the main method after the byte variables.

3

Add the two bytes and assign to sum

Assign the sum of num1 and num2 to the int variable sum using the expression num1 + num2.

Java

public class Main {
    public static void main(String[] args) {
        byte num1 = 10;
        byte num2 = 20;
        int sum;
        // Your code here
    }
}

Need a hint?

Use sum = num1 + num2; to add the bytes and store the result.

4

Print the sum

Print the value of sum using System.out.println.

Java

public class Main {
    public static void main(String[] args) {
        byte num1 = 10;
        byte num2 = 20;
        int sum;
        sum = num1 + num2;
        // Your code here
    }
}

Need a hint?

Use System.out.println(sum); to display the result.