Stopping my function from doing iteration (infinite while loop)

After achieving the desired result the loop continues, how can i stop this? if truefunction y = mysqrt(x,y0,tol) % this function calculates the square root of a number x as y given the % less appropriate guess y0. The function ceases to iterate when the the % difference between y0 and y is less than 1e-3.

 y = (y0 + (x/y0))/2;
 y = (y + (x/y))/2;
 while abs(y-y0)>tol
     y = (y + (x/y))/2

 end

[A K]

woops forgot to add the top line of the script:

function y = mysqrt(x,y0,tol)function

Answer 1

[Azzi Abdelmalek]

function y = mysqrt(x,y0,tol)
y = (y0 + (x/y0))/2;
y = (y + (x/y))/2;
while abs(y^2-x)>tol
   y = (y + (x/y))/2
end

[A K]

ooooooooooooooooohhhhhhhhhhhhh that makes sense!!!! thanks!!!

[A K]

how about when 2 iterations are closer than tol?

[Azzi Abdelmalek]

The while loop will be skipped. The result will be fine

[A K]

No, i mean by setting that as the condition. Is it possible?

[Azzi Abdelmalek]

It's not clear

Answer 2

[John Petersen]

   function y = mysqrt(x,y0,tol)

y = (y0 + (x/y0))/2;
 while abs(y-y0)>tol
     y0 = y;     
     y = (y + (x/y))/2;
 end

Now I see Azzi's answer which is better because it tests against the desired result.