Expression-must-have-pointer-to-object-type

What does the above error mean? I have typdef Coeffs as double and I'm trying to use it in func1
Line 18: Poly --> expression must have pointer to object type

Code:

---


typedef double Coeffs;

int main()
{
        Coeffs Poly;

        ...
}

func1(Coeffs Poly, int num_verts, double*coeff)
{
        double A, B, C, D;
        int i, j;
        A = B = C = D = 0;
        for(i=0;i<num_verts;i++)
        {
                j = (i+1) % num_verts;
                A += ((Poly[j][1] - Poly[i][1]) * (Poly[i][2] + Poly[j][2]));
                B += ((Poly[j][2] - Poly[i][2]) * (Poly[i][0] + Poly[j][0]));
                C += ((Poly[j][0] - Poly[i][0]) * (Poly[i][1] + Poly[j][1]));
        }
}

---

In func1, Poly is a Coeffs, therefore Poly is a double, hence Poly[j][1] does not make sense.