Calculate The Diameter, Circumference and Area of a Circle in java

Question: Write an application that inputs from the user the radius of a circle as an integer and prints the circle’s diameter, circumference and area using the floating-point value 3.14159 for π. Use the techniques shown in Fig. 2.7. [Note: You may also use the predefined constant Math.PI for the value of π. Use the following formulas (r is the radius):

diameter = 2r
circumference = 2πr
area = πr2

Do not store the results of each calculation in a variable. Rather, specify each calculation as the value that will be output in a System.out.printf statement. The values produced by the circumference and area calculations are floating-point numbers. Such values can be output with the format specifier %f in a System.out.printf statement.

Java program to find diameter, circumference and area of circle

/*
 *       Filename:  Circle.java
 *
 *    Description:  Exercise 2.28 - Diameter, Circumference and Area of a Circle
 *
 *			@Author:  Bilal Tahir Khan Meo
 *        	Website: https://www.codeblah.com
 *
 * =====================================================================================
 */
import java.util.Scanner;

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

        int r;

        System.out.print("Enter a circle's radius: ");
        r = input.nextInt();

        System.out.printf("Diameter = %d\nCircumference = %.2f\nArea = %.2f\n",
                            2 * r, 2 * Math.PI * r, Math.PI * r * r);
    }
}

Calculate The Diameter, Circumference and Area of a Circle in java

/**
 *
 *		@Author:  Bilal Tahir Khan Meo
 *        	Website: https://www.codeblah.com
 *
 * Exercise 2.28 - Diameter, Circumference and Area of a Circle
 * This Program Calculates The Diameter, Circumference and Area of a Circle
 *
 */
 
import java.util.Scanner;
 
public class Ex02_28 {
    public static void main (String [] args) {
         
        Scanner value = new Scanner (System.in);
         
        int radius;
         
        System.out.println ("This Application \n");
         
        System.out.print ("Enter The Value For The Radius of The Circle: ");
        radius = value.nextInt();
         
        System.out.printf("\nThe diameter of the circle is %d\nThe circumference "
                + "of the circle is %f\nThe Area of the circle is %f\n",
                (2*radius), (2*Math.PI*radius), (Math.PI*radius*radius));
 
    }
}