public double Calculation(string str)
{
var postfixNotation = notation.Convert2PostfixNotation(str.Replace('.', ','));
var values = new Stack <double>();
foreach (var el in postfixNotation)
{
double resultPars;
values.Push(double.TryParse(el, out resultPars) ? resultPars : el.ApplyTo(values));
}
if (values.Count > 1)
{
throw new Exception("Expression is not valid!");
}
return(values.Pop());
}
