序执行时要求输入序列的长度N_pre，N_pre 是最初输入序列的长度，任意长度都可以。N是指补零后的序列长度，满足2^L.

然后逐个输入各个元素的实部和虚部，补零部分不必输入。

显示FFT变换的结果。-Order execution when the input sequence length requirements N_pre, N_pre are the initial input sequence length, can be of any length. N refers to zero after the sequence length, then 2 ^ L. Satisfied by the importation of all elements of real and imaginary parts, some do not have to enter zero. Shows the results of FFT transform.