MATLAB Programming

9 Classes and Objects
function n = getAccountNumber(p)
% provides a account number for object p
n = [upper(p.name(1:3)) strcat(num2str(round(rand(1,7)*10))')'];
Note that the portfolio object is indexed by field name, and then by numerical
subscript to extract the first three letters. The subsref method must be
written to support this form of subscripted reference.
The Portfolio subsref Method
When MATLAB encounters a subscripted reference, such as that made in the
getAccountNumber function
p.name(1:3)
MATLAB calls the portfolio subsref method to interpret the reference. If
you do not define a subsref method, the above statement is undefined for
portfolio objects (recall that here p is an object, not just a structure).
The portfolio subsref method must support field-name and numeric indexing
for the getAccountNumber function to access the portfolio name field.
function b = subsref(p,index)
% SUBSREF Define field name indexing for portfolio objects
switch index(1).type
case '.'
switch index(1).subs
case 'name'
if length(index)== 1
b = p.name;
else
switch index(2).type
case '()'
b = p.name(index(2).subs{:});
end
end
end
end
Note that the portfolio implementation of subsref is designed to provide
access to specific elements of the name field; it is not a general implementation
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