/* cdelay.c - circular buffer implementation of D-fold delay */void wrap();void cdelay(D, w, p)int D;double *w, **p;{       (*p)--;                      /* decrement pointer and wrap modulo-\((D+1)\) */       wrap(D, w, p);               /* when \(*p=w-1\), it wraps around to \(*p=w+D\) */}