/* ifft.c - inverse FFT */#include <cmplx.h>void fft();void ifft(N, X)complex *X;int N;{    int k;    for (k=0; k<N; k++)         X[k] = conjg(X[k]);                     /* conjugate input */    fft(N, X);                                   /* compute FFT of conjugate */    for (k=0; k<N; k++)         X[k] = rdiv(conjg(X[k]), (double)N);    /* conjugate and divide by \(N\) */}