% Robust...
a=input('side a= ');
b=input('side b= ');
c=input('side c= ');
if ( a <= 0 || b <= 0 || c <= 0)
   disp('not a triangle');
else
  if  ( a == b && b == c)
     disp('equilateral'); 
  elseif  (a==b || b == c || a==c)
     disp('isosceles');
  else
     disp('scalene');
  end
end
% Go now to tangle1.m ... tangle5.m for a variation
