Illustration of tracing a error:

The one way of following the flow of function, or tracing it, is to use the echo function. The echo function, that is a toggle, will show each and every statement as it is executed and also the results from the code. For scripts, merely echo can be typed, but for the functions, name of the function should be identified, for illustration,

echo functionname on/off

>> echo testifelse on

>> testifelse(-2)

% This function will test the debugger

if 3 < x < 6

   disp('In middle of range')

In middle of range

end

We can view from this outcome that the action of if clause was executed.