How to Round Double Float up to Two Decimal Places in Java
It indicates 15 digits just after the decimal place in Java whenever a double data type is used in front of a variable. For example, when representing rupees and other units, we may only need two decimals just after the decimal point.
Java offers the 3 techniques listed here to show double with two decimal places.
- DecimalFormat is used ("0.00")
- Making use of the String.format() Method ("%.2f")
- BigDecimal is used.
Method 1: By using the DecimalFormat
The NumberFormat class's concrete subtype, Java DecimalFormat, is applied to print decimals. This setRoundingMode() function of the class enables the presentation of double numbers with up to two decimals.
The DecimalFormat class, a subclass of NumberFormat, is utilized in Java to format decimal integers. The format supplied in the form of #, with the amount of 0 just after the decimal point representing the number of digits you intend to print, is sent in as parameters when creating an object of this type. The amount is generally round to its maximum value. The format() function, which accepts the integer to be converted as an input, is called by the DecimalFormat class object.
Syntax:
public void setRoundingMode(RoundingMode roundingMode)
It receives the rounded mode as an argument and modifies the setRoundingMode() function of the NumberFormat class. When no rounding mode is specified, NullPointerException is raised.
TwoDecimal1.java
//this program is for rounding the decimal to 2 digits after the decimal place
//importing the required packages
import java.io.*;
import java.util.*;
import java.math.RoundingMode;
import java.text.DecimalFormat;
public class TwoDecimal1
{
// the constructor was created for the class TwoDecimal1
private static final DecimalFormat decfors = new DecimalFormat("0.00");
public static void main(String args[])
{
// a decimal number was initialised
double nums = 12334.91381765423567;
System.out.println("The Given Double Number is : " + nums);
System.out.println("The Double Number is: " + decfors.format(nums)); //12334.91
decfors.setRoundingMode(RoundingMode.DOWN);
System.out.println("\nThe number Before Rounding: " + decfors.format(nums)); //12334.91
decfors.setRoundingMode(RoundingMode.UP);
System.out.println("The number After Rounding Up: " + decfors.format(nums)); //12334.92
}
}
Output
The Given Double Number is: 12334.913817654236
The Double Number is: 12334.91
Before Rounding: 12334.91
After Rounding Up: 12334.92
Dividing and multiplying the integer by 10n (n decimal places)
We first multiplied the value by 10n using the Math class' pow() function in this method. The amount is then reduced to the closest integer. The amount is finally divided by 10n. This allows us to obtain an integer value with n decimal points.
Syntax:
number = Math.round(number*Math.pow(10,n))/Math.pow(10,n);
Decimal.java
//this program is for rounding the decimal to 2 digits after the decimal place
//importing the required packages
import java.io.*;
// Main section of the program
class Decimal{
// Main section
public static void main(String[] args)
{
// a variable is initiallized
double num = 12.985665;
// getting the input as the digits required after the decimal place
int places = 2;
// the number is rounded off
// the methods are pow() and round() are used for rounding the number
num = Math.round(num * Math.pow(10, places))
/ Math.pow(10, places);
// displaying the resultant number
System.out.println(num);
}
}
Output
12.99
Implementing the String.format() Method
The format() function is likewise available in Java for formatting numbers. It is a member of the String class. The technique allows for the appropriate formatting of any integer or text.
We format the integer using %.2f to change it up to two decimal points. Remember that using the String.format() function will result in a half-up round of the amount.
Syntax:
public static String format(String formats, Object... args)
The following two arguments are accepted by the method:
format: What we need is a structured string.
args: The parameters listed in the formatting string's template constructors.
The converted string is returned. If the formatting string has improper syntax, it raises an IllegalFormatException. NullPointerException is also thrown if the formatting is null.
TwoDecimal3.java
//this program is for rounding the decimal to 2 digits after the decimal place
//importing the required packages
import java.io.*;
public class TwoDecimal3
{
public static void main(String args[])
{
// a number was declared
double nums = 101.923875465413;
System.out.println(“The Given Double Number: " + nums);
//The same answer may be obtained using either of the two additional expressions for the second decimal place.
System.out.println("The Double Number is : " + String.format("%.2f", nums));
System.out.format("The formatted Double Number is: %.2f", nums);
}
}
Output
The Given Double Number: is 101.923875465413
The Double Number is : 101.92
The formatted Double Number is: 101.92By Using the BigDecimal
ma may also use Java's BigDecimal Class to show numbers with up to two decimal places. The java.math.BigDecimal package contains it. The ComparableBigDecimal> interface is implemented, subclasses the Numbers class.
The setScale() function is available from the class. This is how the sentence reads
Syntax:
setScale(int newScale, RoundingMode roundingMode)
The technique accepts two arguments:
newScale: The size of the given BigDecimal value.
rounding mode: The type of rounds that you wish to use.
It then provides the BigDecimal, which unoptimized amount is calculated by dividing or multiplication this BigDecimal's unoptimized value even by activation functions of ten to preserve its total value. The scale of the returned BigDecimal is the valuation supplied.
If RoundingMode is set as UNNECESSARY, the procedure raises an ArithmeticException. An enumeration called RoundingMode offers the RoundingMode mentioned before.
BigDecimal is a different approach that we've employed in this software.
doubleValue(). Another double number is created from BigDecimal.
Example:woDecimal4.java
//this program is for rounding the decimal to 2 digits after the decimal place
//importing the required packages
import java.io.*;
import java.math.BigDecimal;
import java.math.RoundingMode;
public class TwoDecimal4
{
public static void main(String args[])
{
// declaring the double number
double number = 121.49586585349;
System.out.println("The Given Double Number is: " + number);
BigDecimal bigd = new BigDecimal(number).setScale(2, RoundingMode.HALF_UP);
double newNume = bigd.doubleValue();
System.out.println(" The required decimal number is: " + newNume);
}
}
Output
The Given Double Number is: 121.49586585349
The required decimal number is: 121.5