Question

How is PI defined in C program?

Answer 1

PI Constant in C++

C++ has a predefined constant in its math library which we can use to access the value of pi wherever needed in our program. Here, _USE_MATH_DEFINES is a #define macro. Later in the program, we use M_PI to access the value of PI. In C++, the value of M_PI is 3.14159265358979323846.