static public SimpleBinaryTreeNode MakeExpTree(ArrayList posfix)
{
if (posfix.Count <= 0)
{
throw new ArgumentNullException("The array list for posfix expression is empty.");
}
var stack = new SimpleLinkedListBasedStack <SimpleBinaryTreeNode>();
int pl = posfix.Count;
foreach (dynamic e in posfix)
{
if (e is double)
{
stack.Push(new SimpleBinaryTreeNode(e));
}
else if (e is SOpr)
{
if (stack.Count < 2)
{
throw new ArithmeticException("At least two numbers are needed to make a expression subtree.");
}
var right = stack.Pop();
var left = stack.Pop();
stack.Push(new SimpleBinaryTreeNode(e, left, right));
}
}
return(stack.Pop());
}
static public double EvaluateExpTreeP(SimpleBinaryTreeNode rtnd)
{
var numbuf = new SimpleLinkedListBasedStack <double>();
ArrayList trvlist = new ArrayList();
SimpleBinaryTreeNode.Traverse(ref trvlist, rtnd, SimpleBinaryTreeNode.PostOrder,
(SimpleBinaryTreeNode nd) => {
if ((nd.Data is SOpr) && (nd.Left.DataType == typeof(double)) && (nd.Right.DataType == typeof(double)))
{
double a = (double)trvlist[trvlist.Count - 2]; //stack 쓰는게 더 적절하지 않았겠냐..? 아 trvlist의 작성이...
double b = (double)trvlist[trvlist.Count - 1];
double r = ((SOpr)(nd.Data)).oprt.Invoke(a, b);
nd.Set(r);
trvlist.RemoveAt(trvlist.Count - 1);
trvlist.RemoveAt(trvlist.Count - 1);
}
});
return((double)trvlist[0]);
}//...책에 있는 방식이 더 간단한데? 애미 ㅋㅋㅋㅋ