Formatted output in Java

16 May

Formatted output in Java

Sometimes in Competitive programming, it is essential to print the output in a given specified format. Most users are familiar with printf function in C. Let us see discuss how we can format the output in Java:

Formatting output using System.out.printf()

This is the easiest of all methods as this is similar to printf in C. Note that System.out.print() and System.out.println() take a single argument, but printf() may take multiple arguments.

class Test

{

public static void main(String args[])

{

int x = 600;

System.out.printf("Printing simple integer: x = %dn", x);

// this will print it upto 2 decimal places

System.out.printf("Formatted with precison: PI = %.2fn", Math.PI);

float n = 9.2f;

// automatically appends zero to the rightmost part of decimal

System.out.printf("Formatted to specific width: n = %.4fn", n);

n = 9324435.3f;

// here number is formatted from right margin and occupies a

// width of 20 characters

System.out.printf("Formatted to right margin: n = %20.4fn", n);

}

Output:
Printing simple integer: x = 600
Formatted with precison: PI = 3.14
Formatted to specific width: n = 9.2000
Formatted to right margin: n = 9324435.0000

System.out.format() is equivalent to printf() and can also be used.

Formatting using DecimalFormat class:

DecimalFormat is used to format decimal numbers.

// Java program to demonstrate working of DecimalFormat

import java.text.DecimalFormat;

class Demo2 {

public static void main(String args[]) {

double num = 234.4567;

// prints only numeric part of a floating number

DecimalFormat ft = new DecimalFormat("####");

System.out.println("Without fraction part: num = " + ft.format(num));

// this will print it upto 2 decimal places

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

System.out.println("Formatted to Give precison: num = " + ft.format(num));

// automatically appends zero to the rightmost part of decimal

// instead of #,we use digit 0

ft = new DecimalFormat("#.000000");

System.out.println("appended zeroes to right: num = " + ft.format(num));

// automatically appends zero to the leftmost of decimal number

// instead of #,we use digit 0

ft = new DecimalFormat("00000.00");

System.out.println("formatting Numeric part : num = " + ft.format(num));

// formatting money in dollars

double income = 34456.789;

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

System.out.println("your Formatted Dream Income : " + ft.format(income));

}

Output:
Without fraction part: num = 234
Formatted to Give precison: num = 234.46
appended zeroes to right: num = 234.456700
formatting Numeric part : num = 00234.46
your Formatted Dream Income : $34,456.79

Formatting dates and parsing using SimpleDateFormat class:

This class is present in java.text package.

// Java program to demonstrate working of SimpleDateFormat

import java.text.ParseException;

import java.text.SimpleDateFormat;

import java.util.Date;

class Demo3

{

public static void main(String args[]) throws ParseException

{

// Formatting as per given pattern in the argument

SimpleDateFormat ft = new SimpleDateFormat("dd-MM-yyyy");

String str = ft.format(new Date());

System.out.println("Formatted Date : " + str);

// parsing a given String

str = "05/20/2021";

ft = new SimpleDateFormat("MM/dd/yyyy");

Date date = ft.parse(str);

// this will print the date as per parsed string

System.out.println("Parsed Date : " + date);

}

Output:
Formatted Date : 20-05-2021
Parsed Date : Thu May 20 00:00:00 IST 2021

Formatted output in Java

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Formatted output in Java