public double Calculator(string expr)
{
PhraseStorage ps = new PhraseStorage();
Lexer l = new Lexer(expr, ref ps);
var index = 0;
return(Calculator(ps, ref index));
}
private double Calculator(PhraseStorage ps, ref int index)
{
var numberStack = new Stack <double>();
var operatorStack = new Stack <PhraseType>();
while (index < ps._strs.Count)
{
var val = ps._strs[index];
var oper = ps._types[index];
var flag = operatorStack.Count == 0;
//number
if (oper == PhraseType.number)
{
numberStack.Push(Convert.ToDouble(val));
}
//+ -
else if (oper == PhraseType.plus || oper == PhraseType.minus)
{
operatorStack.Push(oper);
}
// * /
else if (oper == PhraseType.mutiple || oper == PhraseType.divide)
{
var nextOper = ps._types[index + 1];
index++;
var prevNumber = numberStack.Pop();
var nextNumber = default(double);
var result = default(double);
if (nextOper == PhraseType.number)
{
nextNumber = Convert.ToDouble(ps._strs[index]);
}
else
{
nextNumber = Calculator(ps, ref index);
}
result = oper == PhraseType.mutiple ? prevNumber * nextNumber : prevNumber / nextNumber;
numberStack.Push(result);
}
// (
else if (oper == PhraseType.leftbracket)
{
index++;
numberStack.Push(Calculator(ps, ref index));
}
// )
else if (oper == PhraseType.rightbracket)
{
//计算堆栈结果
var result = Calculator(numberStack, operatorStack);
numberStack.Push(result);
}
index++;
}
return(Calculator(numberStack, operatorStack));
}
public Lexer(string sentence, ref PhraseStorage ps)
{
_ps = ps;
_ps.ClearResult();
_sentence = sentence;
_chArray = _sentence.ToCharArray();
_success = true;
if (!Analyze())
{
//_ps.AddPhraseResult("error", PhraseType.unknown);
throw new ArgumentException("Expression exception");
}
}
