Java program to find the circumference and area of a circle

Java program to find circumference and area of a circle :

In this tutorial, we will learn how to find the area and circumference of a circle using Java. We only need the radius of the circle to find both of these values. Area is ‘PI*radius*radius’ and circumference is ‘2*PI*radius’. Let’s take a look how to calculate these values :

Java Program :

import java.util.Scanner;

public class Main {


    /**
     * Utility function for System.out.println
     *
     * @param message : string to print
     */
    private static void println(String message) {
        System.out.println(message);
    }


    /**
     * Utility function for System.out.print
     *
     * @param message : string to print
     */
    private static void print(String message) {
        System.out.print(message);
    }

    /**
     * main method
     *
     * @throws java.lang.Exception
     */
    public static void main(String[] args) throws java.lang.Exception {
        //1
        double radius, area, circumference;

        //2
        Scanner scanner = new Scanner(System.in);

        //3
        print("Enter the radius of the circle : ");
        radius = scanner.nextDouble();

        //4
        area = Math.PI * radius * radius;
        circumference = 2 * Math.PI * radius;

        //5
        System.out.printf("Area of the circle : %.2f", area);
        println("");
        System.out.printf("Circumference of the circle :%.2f ", circumference);

    }

}

Sample Output :

Enter the radius of the circle : 100
Area of the circle : 31415.93
Circumference of the circle :628.32 

Enter the radius of the circle : 19.4
Area of the circle : 1182.37
Circumference of the circle :121.89 

Enter the radius of the circle : 10
Area of the circle : 314.16
Circumference of the circle :62.83 

Explanation :

1. Create three ‘double‘ variables to store the radius, area and circumference of the circle.
2. Create one ‘Scanner‘ object to take the inputs from the user.
3. Read the ‘radius‘ of the circle.
4. Find out the area and circumference and save the values to ‘area‘ and ‘circumference‘ variables. We are using ‘Math.PI’ for the value of ‘PI‘.
5. Print out the values of area and circumference calculated.

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