How to Round to at Most 2 Decimal Places in Java

Rounding Numbers to Two Decimal Places in Java

In Java, rounding numbers to two decimal places is a common task. This can be achieved using the BigDecimal class, which provides precise arithmetic and rounding capabilities. Here’s a simple code snippet to demonstrate how to round a double to two decimal places:

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import java.math.BigDecimal;

public class DecimalRounder {

    public static double roundToTwoDecimalPlaces(double value) {
        BigDecimal bd = new BigDecimal(value);
        bd = bd.setScale(2, BigDecimal.ROUND_HALF_UP);
        return bd.doubleValue();
    }

    public static void main(String[] args) {
        double originalValue = 123.45678;
        double roundedValue = roundToTwoDecimalPlaces(originalValue);

        System.out.println("Original Value: " + originalValue);
        System.out.println("Rounded Value: " + roundedValue);
    }
}

Explanation:

1. Import BigDecimal: Begin by importing the BigDecimal class, which will be used for precise arithmetic.

2. Define roundToTwoDecimalPlaces method: This method takes a double value as input, converts it to a BigDecimal, and then rounds it to two decimal places using setScale with ROUND_HALF_UP rounding mode.

3. Example in main method: The main method demonstrates how to use the roundToTwoDecimalPlaces method with an example value. It prints the original and rounded values.

This code uses ROUND_HALF_UP rounding mode, which rounds towards “nearest neighbor” unless both neighbors are equidistant, in which case, it rounds up. Adjust the rounding mode as needed based on your requirements.