/// <summary>
/// evaluate answer with multiple answer choices
/// </summary>
/// <param name="answer">answer to evaluate</param>
/// <returns>calculated number of points for the answer</returns>
private int EvaluateMultipleChoiceAnswer(TestSubmissionAnswer answer)
{
var correctAnswers = QuestionWithChoicesTools.GetCorrectAnswersLetters(answer.Question);
var submittedAnswers = QuestionWithChoicesTools.GetSubmittedAnswersLetters(answer);
var allPossibleAnswers = QuestionWithChoicesTools.GetAnswerChoicesLetters(answer.Question);
int correct = 0;
foreach (var possibleAnswer in allPossibleAnswers)
{
if (IsAnswerLetterCorrect(possibleAnswer, correctAnswers, submittedAnswers))
{
correct++;
}
}
double correctRatio = (double)correct / allPossibleAnswers.Length;
return((int)Math.Round(correctRatio * answer.Question.Points));
}
/// <summary>
/// check if value of <see cref="TestQuestion.CorrectAnswer"/> property is valid
/// </summary>
/// <param name="question">question to check</param>
/// <returns>TRUE - valid, FALSE - invalid</returns>
public bool HasValidCorrectAnswer(TestQuestion question)
{
if (question.Type == QuestionType.TextAnswer)
{
return(true);
}
else
{
var correctLetters = QuestionWithChoicesTools.GetCorrectAnswersLetters(question);
var allChoicesLetters = QuestionWithChoicesTools.GetAnswerChoicesLetters(question);
bool allAnswersValid = correctLetters.All(letter => allChoicesLetters.Contains(letter));
bool choicesValid = AreChoicesValid(allChoicesLetters);
if (question.Type == QuestionType.SingleChoice)
{
return(allAnswersValid && choicesValid && correctLetters.Length == 1);
}
else
{
return(allAnswersValid && choicesValid);
}
}
}