void shell(unsigned long n, float a[]){	unsigned long i,j,inc;	float v;	inc=1;	do {		inc *= 3;		inc++;	} while (inc <= n);	do {		inc /= 3;		for (i=inc+1;i<=n;i++) {			v=a[i];			j=i;			while (a[j-inc] > v) {				a[j]=a[j-inc];				j -= inc;				if (j <= inc) break;			}			a[j]=v;		}	} while (inc > 1);}