Accessing arguments in Java - Mini Project: Build & Apply

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Accessing arguments

📖 Scenario: You are creating a simple Java program that takes input values when it starts. These inputs are called arguments. They are like notes you pass to a friend before they begin a task.

🎯 Goal: Build a Java program that reads the first two arguments given when running the program and prints them out.

📋 What You'll Learn

Create a Java class named ArgumentPrinter

Access the first two command-line arguments using args[0] and args[1]

Print the two arguments on separate lines

💡 Why This Matters

🌍 Real World

Many Java programs take input from users or other programs when they start. These inputs help customize what the program does.

💼 Career

Understanding how to access and use command-line arguments is important for writing flexible Java applications and tools.

1

Create the Java class and main method

Write a Java class called ArgumentPrinter with a main method that accepts a String[] args parameter.

Java

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

💡 Need a hint?

Remember, the main method is the entry point of a Java program and must be public static void main(String[] args).

2

Access the first two arguments

Inside the main method, create two String variables named firstArg and secondArg. Assign them the values of args[0] and args[1] respectively.

Java

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

💡 Need a hint?

Use args[0] for the first argument and args[1] for the second.

3

Print the two arguments

Use System.out.println to print firstArg and secondArg on separate lines inside the main method.

Java

public class ArgumentPrinter {
    public static void main(String[] args) {
        String firstArg = args[0];
        String secondArg = args[1];
        // Your code here
    }
}

💡 Need a hint?

Use System.out.println twice, once for each argument.

4

Run and display the output

Run the program with arguments Hello and World and print the output.

Java

public class ArgumentPrinter {
    public static void main(String[] args) {
        String firstArg = args[0];
        String secondArg = args[1];
        System.out.println(firstArg);
        System.out.println(secondArg);
    }
}

// Run the program with arguments "Hello" and "World"

💡 Need a hint?

When running the program, pass Hello and World as arguments to see them printed.