How to Format an Integer in Java

The Java programming language is good at storing numbers, but often numbers must be printed in a certain format. For example, currency is expected to be preceded by a currency symbol and have an appropriate number of decimal places, and often commas are used to mark every three or four digits (depending on your culture) of a large number.

Instructions

1. Open "Netbeans" and select "File" and "New class."

2. Type "psvm" to create a main method.

3. Add the following to the main method:

   // Format integer

   String s = integerFormat(i);

   System.out.println(s);

   This will format an integer using a method named "integerFormat." However, that method doesn't exist yet, so you will define it in the next step.

4. Add the following outside the main method:

   static String integerFormat(int i) {

   DecimalFormat df = new DecimalFormat("$#,###.##");

   String s = df.format(i);

   return s;

   }

   The format syntax is fairly simple. Most digits appear exactly as written in the final number format. Pound signs (#) represent optional numbers. For example, if the number given had decimal places, then "#.##" will show decimal places. But, if there are no decimals places, then the decimals would not appear. On the other hand "0" is a required number. If you replaced "#.##" with "#.00," then the two decimal places would always appear, even if the value doesn't have a decimal value.

5. Click "Run."

References

• Oracle: DecimalFormat