Calculating Rectangle Area in Java: Examples and Code

Réponse :

In Java, calculating the area of a rectangle is a straightforward task that involves using the formula:

[ \text{Area} = \text{length} \times \text{width} ]

To implement this in Java, you can create a simple program that prompts the user for the length and width of the rectangle, calculates the area, and then displays the result.

Example Code

Here’s a basic example of how to get the area of a rectangle in Java:

import java.util.Scanner;

public class RectangleArea {
    public static void main(String[] args) {
        // Create a Scanner object to read input
        Scanner scanner = new Scanner(System.in);

        // Prompt the user for the length and width
        System.out.print("Enter the length of the rectangle: ");
        double length = scanner.nextDouble();

        System.out.print("Enter the width of the rectangle: ");
        double width = scanner.nextDouble();

        // Calculate the area
        double area = length * width;

        // Display the result
        System.out.println("The area of the rectangle is: " + area);

        // Close the scanner
        scanner.close();
    }
}

Explanation of the Code

Importing Scanner: The Scanner class is imported from the java.util package to read user input.
Creating the Scanner Object: An instance of Scanner is created to read input from the console.
User Input: The program prompts the user to enter the length and width of the rectangle. The nextDouble() method is used to read the input as a double.
Calculating the Area: The area is calculated by multiplying the length and width.
Displaying the Result: The calculated area is printed to the console.
Closing the Scanner: The scanner.close() method is called to close the scanner and free up resources.

Example Output

If you run the program and input the length as 5 and the width as 3, the output will be:

Enter the length of the rectangle: 5
Enter the width of the rectangle: 3
The area of the rectangle is: 15.0

Additional Considerations

Input Validation: In a real-world application, you might want to add input validation to ensure that the user enters valid numbers (e.g., positive values).
Object-Oriented Approach: You could also create a Rectangle class with methods to calculate the area, which would be a more object-oriented approach.

Object-Oriented Example

Here’s how you could implement it using a class:

class Rectangle {
    private double length;
    private double width;

    // Constructor
    public Rectangle(double length, double width) {
        this.length = length;
        this.width = width;
    }

    // Method to calculate area
    public double getArea() {
        return length * width;
    }
}

public class RectangleArea {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);

        System.out.print("Enter the length of the rectangle: ");
        double length = scanner.nextDouble();

        System.out.print("Enter the width of the rectangle: ");
        double width = scanner.nextDouble();

        // Create a Rectangle object
        Rectangle rectangle = new Rectangle(length, width);

        // Display the area
        System.out.println("The area of the rectangle is: " + rectangle.getArea());

        scanner.close();
    }
}