Convert Cartesian to Polar using custom functions

Hello! I'm having trouble figuring out how to convert cartesian to polar using only custom functions. I'm extremely new to MATLAB and I haven't been able to find a turotial or help guide online that I can make sense of.

Basically, the user needs to be able to submit an array full of however many points they want, the function then takes that array and converts each point into polar coordinates.

So far I have this:

function [homework5] = Cartesian(X,Y)

M = size(X,1)

for N = M;
if X,Y;

      r=sqrt(X^2+Y^2)
      theta=atan(Y/X)

else
    disp('input incorrect')

end   

   if r > 10
          disp('Far from Origin')
      else
          disp('Close to Origin')

   end

end

It converts one pair just fine but when more than one is entered it doesn't work. I know it's a problem with my for loop and M variable but I just don't know what.

[Walter Roberson]

What is the intention of our line:

if X,Y;

?

Where do you use N ?

[Matt]

For N=1:M

[Mahdi]

I also suggest using 'dot' operators when multiplying and squaring, because you want it to be scalar multiplication, and not matrix multiplication. For example, use

r=sqrt(X.^2+Y.^2)
theta=atan(Y./X)

[Ashton Thorsen]

My intention was to say "if X and Y are submitted then do this" Which I think I'm channeling to much pHp logic into this! I want the for loop to know to run it however many points there are.