How Can I Use the PI Constant in C ?

Using the PI Constant in C

In C , the math.h header file provides access to various trigonometric functions. However, it doesn't explicitly define the PI constant. To use PI without manual definition, consider these options:

Defining _USE_MATH_DEFINES

On certain platforms, including the _USE_MATH_DEFINES macro before including math.h enables access to the PI constant. After defining this macro and including math.h, the PI value can be accessed via the M_PI symbol.

Accessing Predefined Macros

In some math.h files, the PI constant is already defined using macros. You can consult your math.h or reference online resources to check for predefined macros such as M_PI, PI, or PI_256.

Using External Libraries

If the above methods are not applicable or if you require greater precision, consider using external libraries like Boost's Math Library or cpp-pi, which provide high-precision PI values.

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