// 计算表达树
private String Calculate(CalculateTree T)
{
// 操作数左右孩子必为空
if (T.getLchild() == null && T.getRchild() == null)
{
return(T.getValue());
}
String l = "", r = "";
if (T.getLchild() != null)
{
l += Calculate(T.getLchild());
}
if (T.getRchild() != null)
{
r += Calculate(T.getRchild());
}
return(operate(T.getValue(), l, r));
}
// 构造表达树
private void initCalculateTree(String expression)
{
Stack <char> operationStack = new Stack <char>();
Stack <CalculateTree> calculateNodeStack = new Stack <CalculateTree>();
int i = 0;
expression += '\0';
operationStack.Push('\0');
while (i < expression.Length && (expression[i] != '\0' || operationStack.Count != 0))
{
// 过滤掉除操作符和数字以外的字符
spiltChar(expression, ref i);
// 开始建树
if (!isOperationChar(expression[i]) || isNegative(expression, i))
{ // 数字部分
String value = "";
value += expression[i++];
while (Char.IsDigit(expression[i]) || expression[i] == '.')
{
value += expression[i++];
}
CalculateTree T = new CalculateTree(value);
calculateNodeStack.Push(T);
}
else
{
char t = judgPower(expression[i], operationStack.Peek());
switch (t)
{
case '>':
{
operationStack.Push(expression[i++]);
break;
}
case '<':
{
string sign = new string(operationStack.Peek(), 1);
operationStack.Pop();
CalculateTree second = calculateNodeStack.Peek(); // 后操作数
calculateNodeStack.Pop();
CalculateTree first = calculateNodeStack.Peek(); // 前操作数
calculateNodeStack.Pop();
CalculateTree T = new CalculateTree(sign, first, second);
calculateNodeStack.Push(T);
break;
}
case '=':
{
operationStack.Pop();
i++;
break;
}
}
}
}
this.T = calculateNodeStack.Peek();
}
public CalculateTree(String value, CalculateTree lchild = null, CalculateTree rchild = null)
{
this.value = value;
this.lchild = lchild;
this.rchild = rchild;
}