public override double Eval()
{
double left = LeftNode.Eval(); // Left SubTree evaluation
double right = RightNode.Eval(); // Right SubTree evaluation
switch (Operator)
{
case '+':
return(left + right);
case '-':
return(left - right);
case '/':
return(left / right);
case '*':
return(left * right);
}
return(double.NaN); // there was no correct output ERROR
}
