## Introduction

In Java, the `DoubleBinaryOperator` interface is a functional interface that represents an operation upon two `double` operands, producing a `double` result. It is part of the `java.util.function` package and is commonly used for arithmetic operations involving two `double` values.

1. What is `DoubleBinaryOperator`?
2. Methods and Syntax
3. Examples of `DoubleBinaryOperator`
4. Real-World Use Case
5. Conclusion

## 1. What is DoubleBinaryOperator?

`DoubleBinaryOperator` is a functional interface designed for operations on two `double` operands that return a `double` result. It simplifies mathematical computations in functional programming.

## 2. Methods and Syntax

The main method in the `DoubleBinaryOperator` interface is:

• `double applyAsDouble(double left, double right)`: Applies the operator to the given operands and returns the result.

### Syntax

``````DoubleBinaryOperator operator = (double left, double right) -> {
// operation on left and right
return result;
};
``````

## 3. Examples of DoubleBinaryOperator

### Example 1: Adding Two Numbers

``````import java.util.function.DoubleBinaryOperator;

public static void main(String[] args) {
// Define a DoubleBinaryOperator that adds two doubles
DoubleBinaryOperator add = (a, b) -> a + b;

System.out.println("Sum: " + result);
}
}
``````

Output:

``````Sum: 8.7
``````

### Example 2: Multiplying Two Numbers

``````import java.util.function.DoubleBinaryOperator;

public class MultiplicationExample {
public static void main(String[] args) {
// Define a DoubleBinaryOperator that multiplies two doubles
DoubleBinaryOperator multiply = (a, b) -> a * b;

double result = multiply.applyAsDouble(4.0, 2.5);

System.out.println("Product: " + result);
}
}
``````

Output:

``````Product: 10.0
``````

## 4. Real-World Use Case: Calculating Average

In financial applications, `DoubleBinaryOperator` can be used to calculate the average of two double values, such as prices or rates.

``````import java.util.function.DoubleBinaryOperator;

public class AverageCalculator {
public static void main(String[] args) {
// Define a DoubleBinaryOperator to calculate the average of two doubles
DoubleBinaryOperator average = (a, b) -> (a + b) / 2;

double averagePrice = average.applyAsDouble(20.5, 30.0);

System.out.println("Average Price: " + averagePrice);
}
}
``````

Output:

``````Average Price: 25.25
``````

## Conclusion

The `DoubleBinaryOperator` interface is used in Java for performing operations on two `double` operands, returning a `double` result. It is particularly beneficial in scenarios involving mathematical computations, such as financial calculations or scientific applications. Using `DoubleBinaryOperator` can help create concise and readable code in functional programming contexts.