public string Parse(string task)
{
string[] taskInLines = Regex.Split(PrepareTask(task).Replace(" ", ""), "(?<=[-+*/()^])|(?=[-+*/()^])").Where(i => i != "").ToArray();
foreach (var taskLine in taskInLines)
{
if (IsNegative(taskLine))
{
_isCurrentNegative = true;
continue;
}
if (!CalculatorUtilities.IsOperatorOrBracket(taskLine))
{
_convertedTask += (IsNegativeNumber(taskLine) ? "-" : "") + (taskLine + " ");
_isCurrentNegative = false;
}
else
{
OperationsPriorityHandler(taskLine);
}
_taskLineBefore = taskLine;
}
if (_operationsBuffer.Count > 0)
{
OperationsPriorityHandler(isLast: true);
}
return(_convertedTask);
}
private void OperationsPriorityHandler(string currentLine = "", bool emptyTheBracket = false, bool isLast = false)
{
if (isLast)
{
AddLastItemToConvertedTaskString(_operationsBuffer.Pop());
OperationsPriorityHandler(currentLine, isLast: _operationsBuffer.Count > 0);
}
else if (currentLine.Equals(")") || emptyTheBracket)
{
if (_operationsBuffer.Count < 1)
{
return;
}
string currentItem = emptyTheBracket ? currentLine : _operationsBuffer.Pop();
AddLastItemToConvertedTaskString(currentItem);
if (_operationsBuffer.Count < 1)
{
return;
}
string nextItem = _operationsBuffer.Pop();
if (!nextItem.Equals("("))
{
OperationsPriorityHandler(nextItem, emptyTheBracket: true);
}
}
else if (_operationsBuffer.Count == 0)
{
_operationsBuffer.Push(currentLine);
}
else if (CalculatorUtilities.IsCurrentOperationPriorityBigger(currentLine, _operationsBuffer.Peek()))
{
_operationsBuffer.Push(currentLine);
}
else
{
AddLastItemToConvertedTaskString(_operationsBuffer.Pop());
OperationsPriorityHandler(currentLine);
}
}
private static string HandleNegativeBrackets(string task)
{
IEnumerable <string> taskInBrackets = Regex.Split(task.Replace(" ", ""), "([-]{1}[(]{1}|[(]{1}|[)]{1})").Where(i => i != "").ToArray();
string taskWithWrappedNegativeBrackets = "";
var bracketsCache = new Stack <string>();
string lastLine = "";
// Handling negative brackets
foreach (string currentLine in taskInBrackets)
{
if (CalculatorUtilities.IsOperator(lastLine.LastOrDefault().ToString()) && currentLine.Equals("-("))
{
bracketsCache.Push("-(");
taskWithWrappedNegativeBrackets += "(0";
}
if (lastLine.Equals("-(") && currentLine.Equals("-("))
{
taskWithWrappedNegativeBrackets += "0";
}
else if (currentLine.Equals("(") && bracketsCache.Count > 0)
{
bracketsCache.Push("(");
}
else if (currentLine.Equals(")") && bracketsCache.Count > 0 && bracketsCache.Pop().Equals("-("))
{
taskWithWrappedNegativeBrackets += ")";
}
lastLine = currentLine;
taskWithWrappedNegativeBrackets += currentLine;
}
return(taskWithWrappedNegativeBrackets);
}
public double Calculate(string rpnTask)
{
if (string.IsNullOrEmpty(rpnTask))
{
return(0);
}
var task = new List <string>(rpnTask.Split(' '));
var taskBuffer = new Stack <double>();
foreach (var taskLine in task)
{
if (!string.IsNullOrEmpty(taskLine))
{
taskBuffer.Push(
!CalculatorUtilities.IsOperatorOrBracket(taskLine)
? double.Parse(taskLine)
: CalculatorUtilities.Compute(taskLine, taskBuffer.Pop(), taskBuffer.Pop())
);
}
}
return(taskBuffer.Count <= 1 ? taskBuffer.Pop() : taskBuffer.Sum());
}
private bool IsNegativeNumber(string currentLine)
{
return(_isCurrentNegative && !CalculatorUtilities.IsOperatorOrBracket(currentLine));
}
private bool IsNegative(string currentLine)
{
return((_taskLineBefore == "" || _taskLineBefore == "(" || CalculatorUtilities.IsOperator(_taskLineBefore)) && currentLine.Equals("-"));
}
