How to find different coordinates from an array that satisfies the equation of circle?

I am trying to find multiple values of x and y coordinates from an array that satisfies the equation of circle? a = 2; b = 2; r = 2; A = [1:100; 1:100] C(:,2) = A((A(:,1)-a).^2+(A(:,2)-b).^2==r^2,:)

I am not able to define the the variable C such that it gives me multiple values satisfying the equation

Thank you in advance

Answer 1

[John D'Errico]

This:

A = [1:100; 1:100]

does NOT generate combinations of those values in a grid.

a = 2;b=2;r = 2;
[A,B] = meshgrid(1:100,1:100);
[I1,I2] = find((A - a).^2 + (B - b).^2 == r.^2)
I1 =
     4
     2
I2 =
     2
     4

Different values for a, b, and r will potentially generate more solutions.