MATLAB Programming

Example — A Polynomial Class
on the screen. This method produces output that is the same as standard
MATLABoutput.Thatis,thevariablenameisdisplayedfollowedbyanequal
sign, then a blank line, then a new line with the value.
function display(p)
% POLYNOM/DISPLAY Command window display of a polynom
disp(' ');
disp([inputname(1),' = '])
disp(' ');
disp([' ' char(p)])
disp(' ');
The statement
p = polynom([1 0 -2 -5])
creates a polynom object. Since the statement is not terminated with a
semicolon, the resulting output is
p =
x^3 - 2*x - 5
The Polynom subsref Method
Suppose the design of the polynom class specifies that a subscripted reference
to a polynom objectcausesthepolynomialtobeevaluatedwiththevalueofthe
independent variable equal to the subscript. That is, for a polynom object p,
p = polynom([1 0 -2 -5]);
the following subscripted expression returns the value of the polynomial at x
= 3 and x = 4.
p([3 4])
ans =
16 51
subsref Implementation Details
This implementation takes advantage of the char method already defined in
the polynom class to produce an expression that can then be evaluated.
function b = subsref(a,s)
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