球球来个人一次性把NVH中怎么用讲明白啊#include<bits/stdc++.h> usingnamespacestd;constdoublePI=3.14159265358979323846;voidfft(vector<complex<double>>&a,boolinvert){//定义FFT函数   intn=a.size();   if(n==1)return;