# What Is the Double Data Type?

//

Larry Thompson

What Is the Double Data Type?

In HTML, the double data type is a numerical data type used to store floating-point numbers. It is commonly used to represent decimal values in programming languages such as JavaScript and Java. The double data type allows for a greater range of values and higher precision compared to the float data type.

The double data type is defined using the double keyword. It can store both positive and negative numbers, including zero. The size of a double variable varies depending on the programming language and platform, but it typically occupies 8 bytes of memory.

## Declaration and Initialization

To declare and initialize a double variable, you can use the following syntax:

```double variableName;
variableName = initialValue;
```

For example, if we want to declare a double variable called pi and set its initial value to 3.14159, we can write:

```double pi;
pi = 3.14159;
```

Alternatively, you can combine the declaration and initialization in one line:

```double pi = 3.14159;
```

## Precision and Range

One of the advantages of using the double data type is its higher precision compared to other numerical types like float. The double data type can store values with up to 15 decimal places.

The range of values that can be stored in a double variable depends on the programming language you are using. In JavaScript, for example, the minimum value is approximately 5e-324 and the maximum value is approximately 1.7976931348623157e+308.

## Arithmetic Operations

You can perform various arithmetic operations on double variables just like with other numerical data types. Addition, subtraction, multiplication, and division are all supported.

Here’s an example that demonstrates some common arithmetic operations using double variables:

```double num1 = 10.5;
double num2 = 5.2;

double sum = num1 + num2;
double difference = num1 - num2;
double product = num1 * num2;
double quotient = num1 / num2;
```

## Conclusion

In summary, the double data type is a numerical data type used to store floating-point numbers with higher precision compared to the float data type. It allows for a greater range of values and is commonly used to represent decimal values in programming languages.

By understanding how to declare, initialize, and perform arithmetic operations on double variables, you can effectively work with decimal values in your HTML projects.