/// <summary>
/// 计算后缀表达式
/// </summary>
/// <param name="alexpression"></param>
/// <returns></returns>
public static object ComputePostfix(ArrayList alexpression)
{
try
{
//·建立一个栈S
Stack s = new Stack();
int count = alexpression.Count;
int i = 0;
while (i < count)
{
//·从左到右读后缀表达式，读到数字就将它转换为数值压入栈S中，
string word = alexpression[i++].ToString();
if (OperatorMap.IsVar(word))
{
s.Push(word);
// System.Console.WriteLine("Push:{0}",word);
}
else//读到运算符则从栈中依次弹出两个数分别到Y和X，
if (OperatorMap.CheckOperator(word))
{
string y, x, sResult;
if (!CheckOneOperator(word))
{
y = s.Pop().ToString();
x = s.Pop().ToString();
//然后以“X 运算符 Y”的形式计算机出结果，再压加栈S中
sResult = ComputeTwo(x, y, word).ToString();
s.Push(sResult);
}
else
{
x = s.Pop().ToString();
sResult = ComputeOne(x, word).ToString();
s.Push(sResult);
}
}
}
string spop = s.Pop().ToString();
// System.Console.WriteLine("Result:{0}",spop);
return(spop);
}
catch
{
System.Console.WriteLine("Result:表达式不符合运算规则!Sorry!");
return("Sorry!Error!");
}
}
public static object ComputePostfix(ArrayList alexpression)
{
object result;
try
{
Stack stack = new Stack();
int count = alexpression.Count;
int i = 0;
while (i < count)
{
string text = alexpression[i++].ToString();
if (OperatorMap.IsVar(text))
{
stack.Push(text);
}
else
{
if (OperatorMap.CheckOperator(text))
{
if (!CheckOneOperator(text))
{
string sR = stack.Pop().ToString();
string text2 = stack.Pop().ToString();
string obj = ComputeTwo(text2, sR, text).ToString();
stack.Push(obj);
}
else
{
string text2 = stack.Pop().ToString();
string obj = ComputeOne(text2, text).ToString();
stack.Push(obj);
}
}
}
}
string text3 = stack.Pop().ToString();
result = text3;
}
catch
{
Console.WriteLine("Result:表达式不符合运算规则!Sorry!");
result = "Sorry!Error!";
}
return(result);
}
/// <summary>
/// 中缀表达式转换为后缀表达式
/// </summary>
/// <param name="alexpression"></param>
/// <returns></returns>
public static ArrayList ConvertToPostfix(ArrayList alexpression)
{
ArrayList alOutput = new ArrayList();
Stack sOperator = new Stack();
string word = null;
int count = alexpression.Count;
int i = 0;
while (i < count)
{
word = alexpression[i++].ToString();
//·读到左括号时总是将它压入栈中
if (OperatorMap.CheckLeftBracket(word))
{
sOperator.Push(word);
}
else
//·读到右括号时，将*近栈顶的第一个左括号上面的运算符全部依次弹出，送至输出队列后，再丢弃左括号。
if (OperatorMap.CheckRightBracket(word))
{
while (true)
{
if (sOperator.Count == 0)
{
break;
}
string sTop = sOperator.Peek().ToString();
if (sTop == "(")
{
sOperator.Pop(); break;
}
else
{
alOutput.Add(sOperator.Pop());
}
}
}
else
//·当读到数字直接送至输出队列中
if (OperatorMap.IsVar(word))
{
alOutput.Add(word);
}
else
//·当读到运算符t时，
// a.将栈中所有优先级高于或等于t的运算符弹出，送到输出队列中；
// b.t进栈
if (OperatorMap.CheckOperator(word))
{
while (sOperator.Count > 0)
{
string sPop = sOperator.Peek().ToString();
if (sPop == "(")
{
break;
}
if (OperatorMap.GetMaxprior(word, sPop) >= 0)
{
// sPop = sOperator.Pop().ToString();
alOutput.Add(sOperator.Pop().ToString());
}
else
{
break;
}
// System.Console.WriteLine("XH{0}",sPop);
}
sOperator.Push(word);
}
// System.Console.WriteLine("{0}",word.ToString());
}
//中缀表达式全部读完后，若栈中仍有运算符，将其送到输出队列中
while (sOperator.Count > 0)
{
string s = sOperator.Pop().ToString();
alOutput.Add(s);
// System.Console.WriteLine("{0}:{1}",sOperator.Count,s.ToString());
}
return(alOutput);
}
public static ArrayList ConvertToPostfix(ArrayList alexpression)
{
ArrayList arrayList = new ArrayList();
Stack stack = new Stack();
int count = alexpression.Count;
int i = 0;
while (i < count)
{
string text = alexpression[i++].ToString();
if (OperatorMap.CheckLeftBracket(text))
{
stack.Push(text);
}
else
{
if (OperatorMap.CheckRightBracket(text))
{
while (stack.Count != 0)
{
string a = stack.Peek().ToString();
if (a == "(")
{
stack.Pop();
break;
}
arrayList.Add(stack.Pop());
}
}
else
{
if (OperatorMap.IsVar(text))
{
arrayList.Add(text);
}
else
{
if (OperatorMap.CheckOperator(text))
{
while (stack.Count > 0)
{
string text2 = stack.Peek().ToString();
if (text2 == "(" || OperatorMap.GetMaxprior(text, text2) < 0)
{
break;
}
arrayList.Add(stack.Pop().ToString());
}
stack.Push(text);
}
}
}
}
}
while (stack.Count > 0)
{
string value = stack.Pop().ToString();
arrayList.Add(value);
}
return(arrayList);
}
