%
% MATLAB for DUMMIES 11-12
% Exercice 1
%
% Solution detaillee
%  Vincent Legat, Damien Bouvy, Denis-Gabriel Caprace, Gilles De Neyer, 
%  Kevin Degraux, Mohammad Iranmanesh, Christophe Lorant, Remy Moulin, 
%  Matthew Philippe, Karim Slaoui, Olivier Thiry, Laurent Van Eesbeeck,
%  Thomas Vanderstraeten, Antoine Weynants
%
% -------------------------------------------------------------------------
function matlab1()

X = [1 3 5; 4 4 4+100*eps; 4 4 4-100*eps; 1 1 1+eps; 1 1 1-eps;
     3 3 3; 3 3 3; 2 2 1; 1 2 4; 1 2 4];
Y = [4 5 6; 0 1 0; 0 1 0; 0 1 0; 0 1 0; eps -eps eps;
     3 3 3; 2 2 1; 0 0 0; 0 0 5];
result = [0  1 -1  1 -1  0 -2 -2  0 -1];

score = 0;
for j=1:10
    if (whereareyou(X(j,:),Y(j,:)) == result(j)) 
           disp('Bien joué :-'); score = score + 1;
    else   disp('Yek yek : raté !'); end
end
fprintf('Score : %d\n',score);

end

function diagnostic = whereareyou(X,Y)
%WHEREAREYOU Location of a point with respect to a line
%   DIAGNOSTIC = WHEREAREYOU(X,Y) checks the location of (X(3),Y(3))
%   for the line defined by points (X(1),Y(1)) and (X(2),Y(2))
%
%      diagnostic =  1 : right side
%      diagnostic = -1 : left
%      diagnostic =  0 : on the line (exceptional case :-)
%      diagnostic = -2 : the line is ill defined
%
area = (X(2)-X(1))*(Y(3)-Y(1)) - (X(3)-X(1))*(Y(2)-Y(1));

if     (area < 0)                   diagnostic = 1;
elseif (area > 0)                   diagnostic = -1;
else                                diagnostic = 0;
end

if (X(1) == X(2) && Y(1) == Y(2))   diagnostic = -2;
end
     

end