# What Is Decimal Data Type in Java?

//

Scott Campbell

What Is Decimal Data Type in Java?

When working with numbers in Java, there are different data types available to store different kinds of numerical values. One such data type is the decimal data type. The decimal data type is used to represent numbers with a fractional part, also known as floating-point numbers.

## Why Use Decimal Data Type?

The decimal data type is ideal for situations where precision is required, such as financial calculations or scientific computations. Unlike other numerical data types like int or double, the decimal data type can accurately represent decimal values without any loss of precision.

## Syntax of Decimal Data Type

In Java, the decimal data type is represented by the class BigDecimal. To declare a variable of decimal data type, you need to import the java.math.BigDecimal package and follow this syntax:

```import java.BigDecimal;

public class Main {
public static void main(String[] args) {
BigDecimal myDecimal = new BigDecimal("123.45");
// Rest of the code..
}
}
```

In the above example, we have declared a variable named `myDecimal` of the decimal data type and assigned it a value of `"123.45"`. It’s important to note that we are passing the value as a string to ensure precision.

## Performing Arithmetic Operations with Decimal Data Type

The decimal data type provides various methods to perform arithmetic operations on decimal values. Some commonly used methods include:

• `add()`: Used to add two decimal values.
• `subtract()`: Used to subtract one decimal value from another.
• `multiply()`: Used to multiply two decimal values.
• `divide()`: Used to divide one decimal value by another.

Here’s an example demonstrating the use of these arithmetic operations:

public class Main {
public static void main(String[] args) {
BigDecimal num1 = new BigDecimal(“10.50”);
BigDecimal num2 = new BigDecimal(“5.25”);

System.out.println(“Sum: ” + sum);

BigDecimal difference = num1.subtract(num2);
System.println(“Difference: ” + difference);

BigDecimal product = num1.multiply(num2);
System.println(“Product: ” + product);

BigDecimal quotient = num1.divide(num2);
System.println(“Quotient: ” + quotient);
}
}

In the above example, we have performed addition, subtraction, multiplication, and division using the `add()`, `subtract()`, `multiply()`, and `divide()` methods respectively. The output will be:

```Sum: 15.75
Difference: 5.25
Product: 55.125
Quotient: 2.00
```

## Rounding Decimal Values

The decimal data type also provides methods for rounding decimal values for precision control. Some commonly used rounding methods include:

• `setScale()`: Used to set the scale (number of decimal places) of a decimal value.
• `round()`: Used to round a decimal value to the nearest whole number.

Here’s an example demonstrating the use of these rounding methods:

public class Main {
public static void main(String[] args) {
BigDecimal number = new BigDecimal(“123.456789”);

BigDecimal rounded = number.setScale(2, BigDecimal.ROUND_HALF_UP);
System.println(“Rounded Value: ” + rounded);

BigDecimal roundedToWholeNumber = number.round(new MathContext(0));
System.println(“Rounded to Whole Number: ” + roundedToWholeNumber);
}
}

In the above example, we have used the `setScale()` method to round the decimal value to two decimal places and the `round()` method with a `MathContext` parameter set to 0, which rounds the decimal value to the nearest whole number. The output will be:

```Rounded Value: 123.46
Rounded to Whole Number: 123
```

## Conclusion

The decimal data type in Java, represented by the BigDecimal class, is essential for handling precise calculations involving fractional numbers. It ensures accuracy and avoids any issues related to floating-point representation. By utilizing its arithmetic and rounding methods, you can perform various calculations while maintaining precision.

In summary, understanding how to work with the decimal data type is crucial when dealing with applications that require exact numerical computations.