%-------------------------------------%
% Homework 3: problem 3.4             %
% Date: 9/30/02                       %
%                                     %
% Gun Srijuntongsiri                  %
% gs61                                %
% ??????                              %
%-------------------------------------%

% Ask for input of x and y
x = input('Enter x : ');
y = input('Enter y : ');

% First, branch on the sign of x
if x>=0

    % Then, on the sign of y
    if y >= 0
        fun = x+y
    else
        fun = x+y^2
    end
    
else   % x < 0

    % Again, branch on the sign of y
    if  y >= 0
        fun = x^2 + y
    else
        fun = x^2 + y^2
    end
end