/* note #undef's at end of file */
#define FUNC(x,mode,ca,fa,ifa,nf,c) ((*func)(x,mode,ca,fa,ifa,nf,c))

float midpnt(float (*func)(float theta, int mode, float *ca, float *fa, int
    *ifa, int nf, float c), float a, float b, int n, int mode, float *ca,
    float *fa, int *ifa, int nf, float c)
{
	float x,tnm,sum,del,ddel;
	static float s;
	int it,j;

	if (n == 1) {
		return (s=(b-a)*FUNC(0.5*(a+b), mode, ca, fa, ifa, nf, c));
	} else {
		for(it=1,j=1;j<n-1;j++) it *= 3;
		tnm=it;
		del=(b-a)/(3.0*tnm);
		ddel=del+del;
		x=a+0.5*del;
		sum=0.0;
		for (j=1;j<=it;j++) {
			sum += FUNC(x, mode, ca, fa, ifa, nf, c);
			x += ddel;
			sum += FUNC(x, mode, ca, fa, ifa, nf, c);
			x += del;
		}
		s=(s+(b-a)*sum/tnm)/3.0;
		return s;
	}
}
#undef FUNC