Looping output values back as input

I'm pretty new to matlab and (programming in general). I've written a program that inputs 3 points' coordinates (assuming them to be circle centers) and outputs tangent point coordinates between those circles. My question is: how can I make the program take the output tangent points and run them back in as new inputs for a certain number of iterations? I'm sure I need to use a loop, but I'm not sure how to use it for this particular purpose.

Answer 1

[Fangjun Jiang]

InputValue=1;

for k=1:NumberOfIteration
    OutputValue=MyFunction(InputValue);
    InputValue=MyFunction(OutputValue);
end

[Alex]

Oh I see. Thank you. Would you happen to know how to handle the case where the output is conditional - for instance: if the slope between 2 points is infinite, the program handles that one way to produce the tangent point, but if it's not, it handles it another way.

[Fangjun Jiang]

I am not clear about your question. Do you mean if-else statement? Type "help if" to see an example.

[Alex]

Yes, an if-else. For instance, if the slope between 2 points is infinite, the tangent point outputted can't be calculated normally because the infinity term causes the expression to blow up, but otherwise it can be calculated normally.

[Fangjun Jiang]

So, what is your question. You don't know how to use if-else statement in MATLAB?