02: Variables – Giving Your Program a Memory

In our last tutorial, we printed text directly to the screen. But what if we want to store a username, a score in a game, or the price of an item? For that, we use Variables.

Think of a variable as a labeled box. You put data inside the box, give it a name, and then you can use that name later to get the data back.

🏗 The Rules of the Box

In Java, you can't just throw anything into a box. Java is Statically Typed, which means you must tell the computer exactly what kind of data the box will hold before you use it.

The 4 Most Common Data Types

💻 How to Declare a Variable

To create a variable, you follow this simple formula: Type name = value;

public class Main {
    public static void main(String[] args) {
        // 1. Storing a name
        String username = "YourName";

        // 2. Storing an age
        int age = 25;

        // 3. Storing a grade
        double gpa = 3.8;

        // 4. Storing a status
        boolean isDeveloper = true;

        // Now, let's use them!
        System.out.println("User: " + username);
        System.out.println("Age: " + age);
    }
}