CS110 Solution Ball of Twine

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NOTE: Constants should not be declared within a method. Use uppercase for constant identifiers.

import java.util.Scanner;

public class Twine {

// DECLARE CONSTANTS

static final int FEET_PER_POUND = 350;

static final int FEET_PER_MILE = 5280;

public static void main(String[] args) {

// DECLARE VARIABLES

double radius; // THE RADIUS OF THE SPHERICAL BALL IN FEET.

double density; // THE DENSITY OF THE SPHERICAL BALL IN POUNDS PER CUBIC FEET.

double volume; // THE VOLUME OF A SPHERE.

double weight; // THE WEIGHT OF THE BALL IN POUNDS

double length; // THE LENGTH OF THE BALL IN MILES

// DISPLAY THE PROGRAM OBJECTIVE TO THE USER.

System.out.println("The largest ball of twine is located in Cawker City, Kansas.");

System.out.println("This program will calculate the weight of the ball and the number ");

System.out.println("of miles the twine would reach if it were unrolled. ");

// PROMPT THE USER FOR RADIUS AND DENSITY OF THE BALL

Scanner in = new Scanner(System.in);

System.out.print("Enter the radius of the ball of twine in feet : ");

radius = in.nextDouble();

System.out.print("Enter the density of the ball of twine in (pounds/cubic feet) : ");

density = in.nextDouble();

// COMPUTE WEIGHT = DENSITY * VOLUME

// VOLUME OF A SPHERE is 4/3 π radius³

// COMBINING THESE TWO FORMULAS GIVES THE FORMULA FOR WEIGHT

volume = 4.0/ 3.0 * Math.PI * (Math.pow(radius, 3.0));

weight = density * volume;

// COMPUTE THE NUMBER OF MILES THE TWINE WILL REACH IF IT WERE UNROLLED

length = FEET_PER_POUND * weight / FEET_PER_MILE;

// DISPLAY THE WEIGHT AND LENGTH OF THE BALL WITH THREE DECIMAL PLACES

System.out.print("\nThe world's largest ball of twine weights ");

System.out.printf("%.3f", weight);

System.out.print(" pounds and is ");

System.out.printf("%.1f", length);

System.out.print(" miles long. \n\n");

}

}