C语言实现几种不同FFT的方法：其中包括时间抽取的基2 DFT，频率抽取的基2 DFT，分裂基算法、CZT方法等。-C language implementation of several different FFT approach: including the time taken by the base 2 DFT, frequency extraction base 2 DFT, split based algorithm, CZT methods.