funxy.m

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%  Script file: funxy.m
%
%  Purpose: 
%    This program solves the function f(x,y) for a 
%    user-specified x and y, where f(x,y) is defined as:
%                 _
%                |
%                | x + y             x >= 0 and y >= 0
%                | x + y^2           x >= 0 and y < 0
%       f(x,y) = | x^2 + y           x < 0  and y >= 0
%                | x^2 + y^2         x < 0  and y < 0
%                |_
%
%  Record of revisions:
%      Date       Programmer          Description of change
%      ====       ==========          =====================
%    01/13/07    S. J. Chapman        Original code 
%
% Define variables:
%   x     -- First independent variable
%   y     -- Second independent variable
%   fun   -- Resulting function

% Prompt the user for the values x and y
x = input ('Enter the x coefficient: ');
y = input ('Enter the y coefficient: ');
 
% Calculate the function f(x,y) based upon 
% the signs of x and y.
if x >= 0 && y >= 0
   fun = x + y;
elseif x >= 0 && y < 0
   fun = x + y^2;
elseif x < 0 && y >= 0
   fun = x^2 + y;
else
   fun = x^2 + y^2;
end
 
% Write the value of the function.
disp (['The value of the function is ' num2str(fun)]);