基2 fft的基本原理，实现起来可以说是相当的好用，大家赶快分享哦-2 fft-based basic principles to achieve can be said to be quite easy to use, we get to share Oh

设计一个按时间抽取的输入倒位序输出顺序的基2—fft算法程序。-Time taken by designing an inversion input sequence output sequence of the base 2-fft algorithm.