Preformatted Output

[Arthur Buliva]

Suppose you have a method that returns numbers. The numbers have different lengths; that is String.valueOf(number).trim().length() returns different values.

However, I would like to preformat the numbers so that always the length being returned is four. This is what I mean:

Suppose you are returned to the number 123. I need to preformat it to 0123. This retains the value 123 but makes the length to be 4

Suppose this time round its 1. Preformatted should now be 0001. 1024 should remain 1024 as it already is 4 characters long.

How is this achievable?

Thanks.

[Rob Spoor]

Look at java.text.NumberFormat, and its subclass DecimalFormat.

[Joanne Neal]

There's also the String.format() method since Java 1.5

[Arthur Buliva]

import javax.swing.*;
 
class Formatter
{
static public void main(String[] args)
{
int MAX_LENGTH = 4;
String leadingZeros = "0000";
 
String sat = JOptionPane.showInputDialog(null, "Which one?");
sat = sat.toUpperCase();
 
int lengthOfInput = sat.trim().length();
int differenceFromMaximum = MAX_LENGTH - lengthOfInput;
 
System.out.print(leadingZeros.substring(0, differenceFromMaximum) + sat);
}
}

The hard way...