this...
struct Point
{
double x;
double y;
};
and this...
Point Collection [6][2] = {
{1,9.3},
{2,11.5},
{3,12.25},
{4,13.1},
{5,14.2},
{6,16.3}
};
What you're doing there is creating a two dimensional array of points, so 12 points total. I can't be totally sure, but it doesn't look like that is your intent. From your usage of Collection, it looks like you're really trying to just create a 1 dimensional array of 6 points and assign the x and y values using array initialization notation.
If the latter is what you're trying to accomplish, just drop the second dimension, use...
Point Collection [6] = {