Abstract: A circle and circular arc generator has a digital differential analyzer (DDA) for receiving coordinates on and a radius of a circle having its center at a specific point and for generating x and y coordinates on a circle having its center at the origin. THe DDA has a carry detecting section for correcting the x or y coordinates for plotting an ellipse. The x coordinates and the radius of the circle are supplied from the DDA to a subtracter which adds and subtracts the input data to obtain x coordinates of rightmost and leftmost points of the target circle. The x and y coordinates from the DDA are incremented by incrementers and decremented by decrementers so as to obtain four points on the target circle which are symmetrical about the specific point.