ICS3U-Formatting Output

When you are outputting to the console screen using the System.out.println( ) function or System.out.print( )function, you may notice that decimal numbers, times and dates may or may not print out the way you want them to.
The Java language has a system (the java.text library) for formatting objects before they are printed.

Formatting Decimal numbers for output:

Formatting a number before it is printed involves following a number of steps.

import java.text.*;

public class Class1 {

public static void main (String[] args) {

double number = 912.3465;

DecimalFormat x = new DecimalFormat("#####.##");

System.out.println (x.format(number));

}

The steps required for formatting a number:

import the "java text" library.

import java.text.*;

2. Create a "DecimalFormat" object that is used for formatting the number.

DecimalFormat x = newDecimalFormat("#####.##");

The above line creates the object "x" that will be used to format a decimal number to two decimals places with 5 digits before the decimal.

DecimalFormat y = newDecimalFormat("#,###,###.###");

The above line creates the object "y" that will be used to format a decimal number to three decimals places with 7 digits before the decimal and commas between each group if three digits.

Example:

System.out.println (x.format(123.45678) );

The above line of code prints out the following:

912.35

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