Does C Have Double Data Type?


Scott Campbell

Does C Have Double Data Type?

The C programming language is widely known for its simplicity and efficiency. It provides a rich set of data types to accommodate various needs.

One question that often arises is whether C has a double data type. Let’s dive into this topic and explore the answer.

The Basics: Floating-Point Data Types

In C, floating-point numbers are represented using the float and double data types. Both of these are used to store real numbers with decimal points, but they differ in their precision.

The float data type is a single-precision floating-point number, which means it can store values with up to approximately six decimal places. On the other hand, the double data type is a double-precision floating-point number, allowing for greater precision by storing values with up to approximately fifteen decimal places.

Using the Double Data Type in C Programs

To use the double data type in a C program, you simply declare a variable of type double. Here’s an example:

    double myDouble = 3.14159;

In this example, we have declared a variable named ‘myDouble’ and initialized it with the value of pi (approximately).

Precision and Storage Considerations

  • The double data type provides greater precision compared to float, making it suitable for applications that require high accuracy, such as scientific calculations, financial modeling, and simulations.
  • It’s important to note that the double data type consumes more memory than float.

    On most systems, a double takes up 8 bytes of memory, while a float takes up 4 bytes. Therefore, if memory usage is a concern and you can tolerate slightly reduced precision, you may opt for the float data type.

Casting and Conversion

In some cases, you may need to convert a double to another data type or vice versa. C provides various casting mechanisms to facilitate this process. For example:

    double myDouble = 10.5;
    int myInt = (int)myDouble;

In this example, we have casted the value of ‘myDouble’ to an integer using the (int) notation. This will truncate the decimal part and store the integer value in ‘myInt’.


In summary, C does have a double data type for handling floating-point numbers with higher precision compared to the float data type. The double data type is commonly used in applications that require greater accuracy at the cost of increased memory usage.

Remember to choose the appropriate data type based on your specific program requirements.

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