How to Accept Value of Radius and Print Area of a Circle

This is a simple Java program designed to calculate the area of a circle based on the radius provided by the user.

It makes use of the mathematical formula for calculating the area of a circle, which is π (pi) times the square of the radius (π * r^2), where π is approximately 3.14.

In this program:

1. It imports the java.util.Scanner class to read input from the user.
2. It declares two variables, area and radius, to store the calculated area and the radius of the circle, respectively.
3. It creates a Scanner object named scanner to read user input.
4. It prompts the user to enter the radius of the circle by displaying the message "Enter Radius: " and reads the user's input as a floating-point number.
5. It closes the Scanner object to release resources once the input is obtained.
6. It calculates the area of the circle using the formula area = 3.14f * radius * radius. Note that it uses an approximation of π (pi) as 3.14.
7. It uses System.out.printf to display the calculated area with formatting. %6.2f in the printf format string specifies that the floating-point number (area) should be displayed with a total width of 6 characters and 2 decimal places.

import java.util.Scanner;

public class CircleArea {
    public static void main(String[] args) {
        float area, radius;
        Scanner scanner = new Scanner(System.in);

        System.out.print("Enter Radius: ");
        radius = scanner.nextFloat();

        scanner.close();

        area = 3.14f * radius * radius;

        System.out.printf("Area: %6.2f", area);
    }
}