Visual C++ :: Crescent Moon - Calculate Points On This Shape

My question is, I have been tasked to draw this shape,

![Crescent Moon][URL] ....

This is to be done using C++ to write code that will calculate the points on this shape.

Important details.

User Input - Centre Point (X, Y), number of points to be shown, Font Size (influences radius)

Output - List of co-ordinates on the shape.

The overall aim once I have the points is to put them into a graph on Excel and it will hopefully draw it for me, at the user inputted size!

I know that the maximum Radius is 165mm and the minimum is 35mm. I have decided that my base [Font Size][1] shall be 20. I then did some thinking and came up with the equation.

Radius = (Chosen Font Size/20)*130. This is just an estimation, I realise it probably not right, but I thought it could work at least as a template.

I then decided that I should create two different circles, with two different centre points, then link them together to create the shape. I thought that the INSIDE line will have to have a larger Radius and a centre point further along the X-Axis (Y staying constant), as then it could cut into the outside line.*

*(I know this is not what it looks like on the picture, just my chain of thought as it will still give the same shape)

So I defined 2nd Centre point as (X+4, Y). (Again, just estimation, thought it doesn't really matter how far apart they are).

I then decided Radius 2 = (Chosen Font Size/20)*165 (max radius)

So, I have my 2 Radii, and two centre points.

This is my code so far (it works, and everything is declared/inputted above)

for(int i=0; i<=n; i++) //output displayed to user {
Xnew = -i*(Y+R1)/n; //calculate x coordinate
Ynew = pow((((Y+R1)*(Y+R1)) - (Xnew*Xnew)), 0.5); //calculate y coordinate

[Code] ....

I am having the problem drawing the crescent moon that I cannot get the two circles to have the same starting point?

I have managed to get the results to Excel. Everything in that regard works. But when i plot the points on a graph on Excel, they do not have the same starting points. Its essentially just two half circles, one smaller than the other (Stops at the Y axis, giving the half doughnut shape).

If this makes sense, I am trying to get two parts of circles to draw the shape as such that they have the same start and end points. Currently all I am getting more a 'half doughnut' shape, due to the circles not being connected.