How to get coordinates on a circle -

I need to drag a line from a point and draw a circle for the circle of each circle. I start drawing a line X, y and stop x, y then stop x, coordinates on y circle. So how to get all the coordinates in the circle.

Usually you calculate like a circle

  x = Radius * cos (angle); Y = radius * sin (angle);   
 and may be different from two angles 0 to 2 * pi  
 If the circle is a center other than 0,0, then you  
  x = cx + radius * cos (angle); Y = C + radius * sin (angle);   
 With Center Coordination (CX, Sai).  
 Attracting a circle depends on your toolkit. Most graphic toolkits provide outside of the box. You need to look at your API.