I m getting two different output in the programs which are almost same.
just the difference is '.0'. In the first program I have not added 'x.0' after the digits(where x is the integral part). and this thing is giving me 2 different answers.

Please explain why am I getting answers like that???

Code for the first program

1.

public class Exercise4 {
public static void main(String[] args){
double diameterSun = 865000;
double diameterEarth= 7600;
double volumeSun = 0;
double volumeEarth=0;
double radiusSun= diameterSun/2;
double radiusEarth = diameterEarth/2;
double fourOverThree = (4/3);
volumeSun =(double) (fourOverThree*(Math.PI)*(Math.pow(radiusSun,3)));
volumeEarth =(double) (fourOverThree*(Math.PI)*(Math.pow(radiusEarth,3)) );
double ratioVolume = (volumeSun/volumeEarth);

System.out.println("Volume of Sun = "+volumeSun+"\nVolume of Earth = "+volumeEarth+
"\n Ratio = "+ratioVolume);

}
}




the code for the 2nd version.


2.

public class Exercise4 {
public static void main(String[] args){
double diameterSun = 865000.0;
double diameterEarth= 7600.0;
double volumeSun = 0.0;
double volumeEarth=0.0;
double radiusSun= diameterSun/2.0;
double radiusEarth = diameterEarth/2.0;
double fourOverThree = (4.0/3.0);
volumeSun =(double) (fourOverThree*(Math.PI)*(Math.pow(radiusSun,3)));
volumeEarth =(double) (fourOverThree*(Math.PI)*(Math.pow(radiusEarth,3)) );
double ratioVolume = (volumeSun/volumeEarth);

System.out.println("Volume of Sun = "+volumeSun+"\nVolume of Earth = "+volumeEarth+
"\n Ratio = "+ratioVolume);

}
}

Change the calculation of "fourOverThree" to the following:
double fourOverThree = (4.0/3.0);
Although the ratiovolume is the same for both programs, the values for volumeSun and volumeEarth are different because when you initialize fourOverThree using:
double fourOverThree = (4/3);
the 4 and 3 are 32 bit integer literals. After the calculation, the answer is widened to 64 bit precison and stored in the double variable fourOverThree. Using integers in the calculation only provides 32 bits of precision resulting in smaller values in the following calculations.

public class Exercise4 {
public static void main(String[] args){
double diameterSun = 865000;
double diameterEarth= 7600;
double volumeSun = 0;
double volumeEarth=0;
double radiusSun= diameterSun/2;
double radiusEarth = diameterEarth/2;
double fourOverThree = (4.0/3.0);
volumeSun =(double) (fourOverThree*(Math.PI)*(Math.pow(radiusSun,3)));
volumeEarth =(double) (fourOverThree*(Math.PI)*(Math.pow(radiusEarth,3)) );
double ratioVolume = (volumeSun/volumeEarth);

System.out.println("Volume of Sun = "+volumeSun+"\nVolume of Earth = "+volumeEarth+
"\n Ratio = "+ratioVolume);

}
}