public double Visit(BinaryExpr bin)
{
if (bin.OP == OPERATOR.PLUS)
{
return(bin.Left.accept(this) + bin.Right.accept(this));
}
else if (bin.OP == OPERATOR.MUL)
{
return(bin.Left.accept(this) * bin.Right.accept(this));
}
else if (bin.OP == OPERATOR.DIV)
{
return(bin.Left.accept(this) / bin.Right.accept(this));
}
else if (bin.OP == OPERATOR.MINUS)
{
return(bin.Left.accept(this) - bin.Right.accept(this));
}
return(Double.NaN);
}
static void Main(string[] args)
{
Expr r = new BinaryExpr(new Number(2),
new BinaryExpr(new Number(3), new Number(4), OPERATOR.MUL),
OPERATOR.PLUS);
double n = r.accept(new TreeEvaluatorVisitor());
Console.WriteLine(n);
r.accept(new ReversePolishEvaluator());
Console.WriteLine();
StackEvaluator s = new StackEvaluator();
r.accept(s);
Console.WriteLine(s.get_value());
Console.WriteLine();
r = new BinaryExpr(
new UnaryExpr(new Number(10), OPERATOR.MINUS), new Number(15), OPERATOR.PLUS);
s = new StackEvaluator();
r.accept(s);
Console.WriteLine(s.get_value());
r.accept(new ReversePolishEvaluator());
Console.Read();
}
public double Visit(BinaryExpr bin)
{
bin.Left.accept(this);
bin.Right.accept(this);
if (bin.OP == OPERATOR.PLUS)
{
eval_stack.Push(eval_stack.Pop() + eval_stack.Pop());
}
else if (bin.OP == OPERATOR.MUL)
{
eval_stack.Push(eval_stack.Pop() * eval_stack.Pop());
}
else if (bin.OP == OPERATOR.DIV)
{
eval_stack.Push(eval_stack.Pop() / eval_stack.Pop());
}
else if (bin.OP == OPERATOR.MINUS)
{
eval_stack.Push(eval_stack.Pop() - eval_stack.Pop());
}
return(Double.NaN);
}
public double Visit(BinaryExpr bin)
{
bin.Left.accept(this);
bin.Right.accept(this);
if (bin.OP == OPERATOR.PLUS)
{
Console.Write(" + ");
}
else if (bin.OP == OPERATOR.MUL)
{
Console.Write(" * ");
}
else if (bin.OP == OPERATOR.DIV)
{
Console.Write(" / ");
}
else if (bin.OP == OPERATOR.MINUS)
{
Console.Write(" - ");
}
return(Double.NaN);
}
