Introduction - If you have any usage issues, please Google them yourself
Function Description: This package is a generic fast Fourier transform C language function, portable and strong, the following section does not depend hardware. This package is used to represent a complex form of the Commonwealth, as the natural order of the complex input (input can make complex real number is the imaginary part is 0), output after FFT transform the natural order of the complex. This package can be initialized call create_sin_tab () function to create a sine function table,