/// <summary>
/// 计算
/// </summary>
/// <param name="ops">操作符的反向栈</param>
/// <param name="nums">操作数的反向栈</param>
/// <returns>最终结果</returns>
public static int Calculate(Stack ops, Stack nums)
{
// 生成两个栈供使用
Stack opStack = new Stack();
Stack numStack = new Stack();
// 开始入栈计算
numStack.Push(nums.Pop());
while (nums.Count != 0)
{
numStack.Push(nums.Pop());
Operator thisOp = (Operator)ops.Pop();
if (ops.Count != 0)
{
Operator nextOp = (Operator)ops.Peek();
// 比较优先级，若当前运算符优先级大于等于下一个运算符，则先运算
if (thisOp.getPriority() >= nextOp.getPriority())
{
int x2 = (int)numStack.Pop();
int x1 = (int)numStack.Pop();
int result = thisOp.doCal(x1, x2);
numStack.Push(result);
}
else
{
opStack.Push(thisOp);
}
}
else
{
opStack.Push(thisOp);
}
}
// 确保运算完全完成
Stack restOps = new Stack(opStack);
Stack restNums = new Stack(numStack);
while (restOps.Count != 0)
{
int x1 = (int)restNums.Pop();
int x2 = (int)restNums.Pop();
restNums.Push(((Operator)restOps.Pop()).doCal(x1, x2));
}
return((int)restNums.Pop());
}
public ArrayList InputToPostfix()
{
Stack <Token> operatorStack = new Stack <Token>();
ArrayList postfixExpr = new ArrayList();
//loop over the tokenized infix expression from user input
try
{
foreach (Token currToken in inputTokens)
{
//if current token is an operand, add to output expression
if (currToken is Operand)
{
postfixExpr.Add(currToken);
}
else if (currToken is Operator)
{
//if current operator is a '(', add it to op stack
if (currToken.getValue().Equals("("))
{
operatorStack.Push(currToken);
}
//if current operator is a ')', pop from stack and add to output until '(' is encountered
else if (currToken.getValue().Equals(")"))
{
Token topStackToken = operatorStack.Pop();
while (!(topStackToken.getValue().Equals("(")))
{
postfixExpr.Add(topStackToken);
topStackToken = operatorStack.Pop();
}
}
//operators that are not parentheses
else
{
Operator currOpToken = currToken as Operator;
Operator currStackToken = new Operator("");
while ((!(operatorStack.Count() == 0)) && ((currStackToken = (Operator)operatorStack.Peek()).getPriority() >= currOpToken.getPriority()))
{
//add tokens from stack to output expression while the current token has <= priority than top of stack
currStackToken = operatorStack.Pop() as Operator;
postfixExpr.Add(currStackToken);
}
operatorStack.Push(currToken);
}
}
}
}
catch (System.InvalidOperationException)
{
return(new ArrayList());
}
//add remainder of stack to postfix expression
while (!(operatorStack.Count() == 0))
{
postfixExpr.Add(operatorStack.Pop());
}
return(postfixExpr);
}
