public static string Solve(string question)
        {
            var postfixExpression = PostfixBuilder.BuildPostfixExpression(question);
            var answer            = PostfixCalculator.Calculate(postfixExpression).ToString();

            return(answer);
        }
 public string T12_CanBuildUnaryMinus(string infixExpression) =>
 PostfixBuilder.BuildPostfixExpression(infixExpression);
 public string T10_CanBuildBrackets(string infixExpression) =>
 PostfixBuilder.BuildPostfixExpression(infixExpression);
 public void T11_CanNotBuildBadBrackets(string infixExpression, Type exceptionType) =>
 Assert.Throws(exceptionType, () => PostfixBuilder.BuildPostfixExpression(infixExpression));
 public string T08_CanBuildSinglePriority(string infixExpression) =>
 PostfixBuilder.BuildPostfixExpression(infixExpression);
 public string T09_CanBuildSeveralPriorities(string infixExpression) =>
 PostfixBuilder.BuildPostfixExpression(infixExpression);
 public string T07_CanBuildSameDifferentOperation(string infixExpression) =>
 PostfixBuilder.BuildPostfixExpression(infixExpression);
 public string T06_CanBuildSamePlusOperation(string infixExpression) =>
 PostfixBuilder.BuildPostfixExpression(infixExpression);
 public void T03_CanNotBuildNull(string infixExpression, Type exceptionType) =>
 Assert.Throws(exceptionType, () => PostfixBuilder.BuildPostfixExpression(infixExpression));
 public string T02_CanBuildOperand(string infixExpression) =>
 PostfixBuilder.BuildPostfixExpression(infixExpression);
 public string T01_CanBuildEmpty(string infixExpression) =>
 PostfixBuilder.BuildPostfixExpression(infixExpression);