public Op(Node l, Node r, string op)
{
this.left = l;
this.right = r;
this.operat = op;
}
public static Node Diff(Node n)
{
if (n is Variable)
{
return new Number(1);
}
if (n is Number)
{
return new Number(0);
}
if (n is Op)
{
Op expr = (Op) n;
if (expr.operat == "Add")
{
return new Op(Diff(expr.left), Diff(expr.right),"Add");
}
if (expr.operat == "Mult")
{
return new Op(new Op(expr.left, Diff(expr.right), "Mult"), new Op(Diff(expr.left), expr.right, "Mult"), "Add");
}
else
return null;
}
else return null;
}