GravityV1.java

/**
 * Calculates surface gravity using static methods given planet stats.
 * 
 * @author Bijan Tajmir
 * @version 12/5/2014
 */
import java.io.IOException;
import java.io.PrintWriter;
import java.io.File;
public class GravityV1
{
    public static double[] resultantGravity( double []kg, double[]km)
    {   double gravitationNum = 6.67E-11; //given gravitational constant
        double []resultantGravities= new double[9]; //initialize array
        for(int iteration = 0; iteration < resultantGravities.length;iteration++)
        {
            resultantGravities[iteration] = ((gravitationNum * kg[iteration]) / (Math.pow(km[iteration]/2,2))); //given formula from lecture notes
        }
        return resultantGravities; //requires return statement to execute
    }
    public static void outputResults(String [] planet, double [] diameter, double [] kg, double[]gForce)
    {   
        System.out.printf("%32s\n","Planetary Data");
        System.out.printf("%-12s %-17s %7s %11s\n","Planet","Diameter(Km)","Mass(Kg)","g(m/s^2)");
        System.out.println("--------------------------------------------------");        
        for(int iterate = 0; iterate < 9; iterate++)
        {
            System.out.printf("%-14s %-14.0f %5.2e %11.2f\n",planet[iterate],diameter[iterate],kg[iterate],gForce[iterate]);
        }
    }
    public static void tableData(double[] gForce)throws IOException
    {
       PrintWriter outFile = new PrintWriter(new File("gravity1.txt"));
       double []resultGravity = gForce; 
       for(int index = 0; index < resultGravity.length;index++)
       {
           outFile.println(resultGravity[index]);
       }
       outFile.close(); //close file writing to end loop
    }
    public static void main(String[]args) throws IOException
    {
        String [] planet = {"Mercury","Venus","Earth","Mars","Jupiter","Saturn","Uranus","Neptune","Pluto"};
        //data from given table
        double [] kg = {3.30E23,4.869E24,5.972E24,6.4219E23,1.900E27,5.68E26,8.683E25,1.0247E26,1.27E22};
        double [] km = {4880000,12103600,12756300,6794000,142984000,120536000,51118000,49532000,2274000};
        double [] diameter = {4880,12103.6,12756.3,6794,142984,120536,51118,49532,2274 };
        double [] gForce = resultantGravity(kg, km);
        outputResults(planet, diameter, kg, gForce);
        tableData(gForce);
    }
}