r->r = 0.5 * t;
res.r = 0.5 * t;
void c_sqrt(complex *r, complex *z)#endif{double mag, t;if( (mag = f__cabs(z->r, z->i)) == 0.)	r->r = r->i = 0.;else if(z->r > 0)	{	r->r = t = sqrt(0.5 * (mag + z->r) );	t = z->i / t;	r->i = 0.5 * t;	}else	{	t = sqrt(0.5 * (mag - z->r) );	if(z->i < 0)		t = -t;	r->i = t;	t = z->i / t;	r->r = 0.5 * t;	}}