source: doc/theses/jiada_liang_MMath/testP1.java @ 4db0140

import java.io.*;

public class testP1 {
    public enum Planet {
                //          mass      radius
                MERCURY ( 3.303E23, 2.4397E6 ),
                VENUS   ( 4.869E24, 6.0518E6 ),
                EARTH   ( 5.976E24, 6.37814E6 ),
                MARS    ( 6.421E23, 3.3972E6 ),
                JUPITER ( 1.9E27,   7.1492E7 ),
                SATURN  ( 5.688E26, 6.0268E7 ),
                URANUS  ( 8.686E25, 2.5559E7 ),
                NEPTUNE ( 1.024E26, 2.4746E7 );

                private final double mass;   // in kilograms
                private final double radius; // in meters

                Planet( double mass, double radius ) {
                        this.mass = mass;
                        this.radius = radius;
                }
                private double mass() { return mass; }
                private double radius() { return radius; }

                // universal gravitational constant  (m3 kg-1 s-2)
                public static final double G = 6.67300E-11;

                double surfaceGravity() {
                        return G * mass / ( radius * radius );
                }
                double surfaceWeight( double otherMass ) {
                        return otherMass * surfaceGravity();
                }
    }
    public static void main( String[] args ) {
                if ( args.length != 1 ) {
                        System.err.println( "Usage: java Planet <earth_weight>" );
                        System.exit( -1 );
                }
                double earthWeight = Double.parseDouble( args[0] );
                double mass = earthWeight / Planet.EARTH.surfaceGravity();
                for ( Planet p : Planet.values() )
                        System.out.printf( "Your weight on %s is %f%n", p, p.surfaceWeight( mass ) );
    }
}

// java test