private void PushUp(ExpressionOperateNode preNode, ExpressionOperateNode curNode)
{
var tmpNode = GetRoot(preNode);
curNode.Node0 = tmpNode;
tmpNode.Parent = curNode;
}
private ExpressionOperateNode GetRoot(ExpressionOperateNode node)
{
while (node != null && node.HasParent())
{
node = node.Parent;
}
return(node);
}
public ExpressionTree(string expr)
{
try
{
exp = expr;
_root = GenerateExpressionTree(expr);
Calculate();
}
catch (Exception e)
{
throw new BasicCalculatorException("输入的表达式有误！");
}
}
private void PushDown(ExpressionOperateNode preNode, ExpressionOperateNode curNode)
{
curNode.Node0 = preNode.Node1;
preNode.Node1 = curNode;
curNode.Parent = preNode;
}
private ExpressionOperateNode GenerateExpressionTree(string expr)
{
StringBuilder tmp = new StringBuilder();
ExpressionNode curLeafNode = null;
ExpressionOperateNode curOperatorNode = null;
bool ForceUp = false;
expr = expr + ".";
for (int i = 0; i < expr.Length; i++)
{
if (IsNum(expr[i]))
{
tmp.Append(expr[i]);
}
else
{
if (tmp.Length != 0)
{
float num = float.Parse(tmp.ToString());
tmp.Clear();
curLeafNode = new ExpressionNumNode(num);
_numNodes.Add(curLeafNode);
if (curOperatorNode != null)
{
curOperatorNode.Node1 = curLeafNode;
}
}
if (ForceUp && curOperatorNode != null)
{
curOperatorNode.Node1 = curLeafNode;
}
if (IsOperator(expr[i]))
{
var tmpOperateNode = new ExpressionOperateNode(expr[i], curLeafNode, null);
if (curLeafNode != null && !curLeafNode.IsNumber)
{
((ExpressionOperateNode)curLeafNode).Parent = tmpOperateNode;
}
_operatorNodes.Add(tmpOperateNode);
if (IsHighOperator(expr[i]) && curOperatorNode != null)
{
PushDown(curOperatorNode, tmpOperateNode);
}
else if ((IsLowOperator(expr[i]) && curOperatorNode != null) ||
(ForceUp && curOperatorNode != null))
{
PushUp(curOperatorNode, tmpOperateNode);
if (ForceUp)
{
ForceUp = false;
}
}
curOperatorNode = tmpOperateNode;
}
else
{
if (!IsBracket(expr[i]) || expr[i] != '(')
{
continue;
}
curLeafNode =
GenerateExpressionTree(expr.Substring(i + 1, SearchMatchBracket(expr, i) - i - 1));
i = SearchMatchBracket(expr, i);
if (curOperatorNode != null)
{
curOperatorNode.Node1 = curLeafNode;
if (curLeafNode != null && !curLeafNode.IsNumber)
{
((ExpressionOperateNode)curLeafNode).Parent = curOperatorNode;
}
}
ForceUp = true;
}
}
}
return(GetRoot(curOperatorNode));
}
