% \insert '../assignment1/List.oz'

declare QuadraticEquation Sum RightFold Quadratic LazyNumberGenerator TailRecursiveSum in

% task 1 a)
proc {QuadraticEquation A B C ?RealSol ?X1 ?X2} Discriminant in
    Discriminant = B*B - 4.0*A*C
    RealSol = Discriminant >= 0.0
    if RealSol then
        X1 = (~B - {Sqrt Discriminant})/(2.0*A)
        X2 = (~B + {Sqrt Discriminant})/(2.0*A)
    end
end
% task 1 b)
local
    TestQuad = proc {$ A B C}
        local RealSol X1 X2 in
            {QuadraticEquation A B C RealSol X1 X2}
            {System.show RealSol|[X1 X2]}
        end
    end
in
    {System.show 'testing abc'}
    {TestQuad 2.0 1.0 ~1.0}
    {TestQuad 2.0 1.0 2.0}
end