Java Celestial Volume Calculator: Earth and Sun Volumes Comparison

This Java program calculates and displays information about the volumes of the Earth and the Sun. It also show the ratio of their volumes. Here’s a step-by-step explanation for a novice Java programmer:

Variable Initialization:

• sunRad and earthRad are initialized with the radii of the Sun and Earth respectively.
• fourOverThree is set to the value of 4.0 divided by 3.0.
• sunVol, earthVol, and ratioVol are declared and initialized to 0.

Volume Calculation:

• Using the formula for the volume of a sphere (V = 4/3 * π * r^3), the program calculates the volumes of the Earth (earthVol) and the Sun (sunVol).
• Math.pow(x, y) is used to raise a number to the power of another.

Volume Ratio Calculation:

• The program calculates the ratio of the Sun’s volume to the Earth’s volume (ratioVol).

Output in Words:

• The program then prints the results to the console using System.out.println.
• The volumes of the Earth and the Sun are displayed in cubic miles, and the ratio of the Sun’s volume to the Earth’s volume is shown.

Additional Method (convertToWords):

• To make the output more readable we have written a method called convertToWords.
• This method takes a double value and converts it to words, appending appropriate unit names (thousand, million, etc.).

public class Volumes
{
  public static void main(String[] args)
  {
    // Initialize a double variable to be the sun's diameter
    double sunRad = 865000.0/2.0;
    double earthRad = 7926.4/2.0;
    double fourOverThree = 4.0/3.0;
    double sunVol = 0, earthVol = 0; // You can declare a number of variables
    double ratioVol = 0;             // of the same type on a single line if you wish.

    // Find the volumes of earth and sun
    earthVol = fourOverThree*Math.PI*Math.pow(earthRad,3);
    sunVol = fourOverThree*Math.PI*Math.pow(sunRad,3);
    
    // Find the ratio of their volumes
    ratioVol = sunVol/earthVol;

    // Output the results in words
    System.out.println("Volume of the earth is approximately " + convertToWords(earthVol) + " cubic miles.");
    System.out.println("Volume of the sun is approximately " + convertToWords(sunVol) + " cubic miles.");
    System.out.println("The sun's volume is approximately " + convertToWords(ratioVol) +
                    " times greater than the earth's.");
  }

  // Method to convert a double value to words
  private static String convertToWords(double value) {
    String[] units = {"", "thousand", "million", "billion", "trillion", "quadrillion"};
    int i = 0;
    while (value >= 1000) {
      value /= 1000;
      i++;
    }
    return String.format("%.2f %s", value, units[i]);
  }
}