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Controlling Decimal Output
(Printing Money)

It is often necessary to print values with a designated number of decimal places.  For example, when printing amounts of money, it is customary to have two decimal places printed to the right of the decimal point.  The money amounts of  $15.1 and  $53.9 are more commonly seen as  $15.10 and  $53.90. 

To insure that a designated number of decimal places will be printed, we will need to utilize the Decimal Format Class.  It will be necessary to include:

 import java.text.*;

You will need to create an object of the class DecimalFormat using a String pattern.
    
DecimalFormat  variable_name =  new DecimalFormat("000.000");
The String pattern will designate how your display will look.  The number of zeros in front of the decimal point will be the minimum number of locations printed to the left of the decimal.  The number of zeros behind the decimal point will be the maximum number of locations printed to the right of the decimal.  With the pattern shown above, the number 45.66844 would print as 045.668.

Sample program:

import java.io.*;
import java.text.*;

public class DecimalTest
{
     public static void main(String[ ] args)
     {
           double money = 15.9;
           double mula = 36.56789;
           DecimalFormat decFor = new DecimalFormat("0.00");

           System.out.println(decFor.format(money)+"\n"+  
                                                                   decFor.format(mula));

     }
}

Screen output:

15.90
36.57

 

 

Things to Remember about the DecimalFormat class:

1.  needs import java.text.*;

2.  the pattern establishes how the output will look - "00.00" - the zeroes in front of the point will be the minimum number of digits displayed.  The zeros after the point will be the maximum number of digits displayed.

3.  it rounds.

4.  it is necessary to specify EACH value you wish printed in this formatted pattern.
 

 


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