public override object GenerateQuestion(Difficulty difficulty)
{
PercentageProblem problem = new PercentageProblem();
Random rand = new Random();
problem.Base = rand.Next(1, 10) * 10;
problem.Percent = rand.Next(1, 10) * 10;
problem.Amount = Percentage(problem.Percent, problem.Base);
switch (rand.Next(3))
{
case 0:
problem.MissingPart = PercentageProblemPart.Amount;
break;
case 1:
problem.MissingPart = PercentageProblemPart.Percent;
break;
case 2:
problem.MissingPart = PercentageProblemPart.Base;
break;
default:
throw new Exception("Missing part generated was not valid.");
}
return(problem);
}
public override bool IsCorrect(object problem, int answer)
{
PercentageProblem p = (PercentageProblem)problem;
switch (p.MissingPart)
{
case PercentageProblemPart.Amount:
return(p.Amount == answer);
case PercentageProblemPart.Percent:
return(p.Percent == answer);
case PercentageProblemPart.Base:
return(p.Base == answer);
default:
return(false);
}
}
public static void PrintQuestion(this PercentageProblem pp, int questionNumber)
{
switch (pp.MissingPart)
{
case PercentageProblemPart.Amount:
Console.WriteLine($"({questionNumber}) _ is {pp.Percent}% of {pp.Base}");
break;
case PercentageProblemPart.Percent:
Console.WriteLine($"({questionNumber}) {pp.Amount} is _% of {pp.Base}");
break;
case PercentageProblemPart.Base:
Console.WriteLine($"({questionNumber}) {pp.Amount} is {pp.Percent}% of _");
break;
default:
throw new ArgumentOutOfRangeException(paramName: nameof(pp.MissingPart), message: $"Missing Part is '{pp.MissingPart}'.");
}
}
public static void AskPercentageQuestion(Generator generator)
{
Percentages subject = new Percentages();
var questionCount = generator.QuestionCount;
var currentQuestion = 1;
while (currentQuestion <= questionCount)
{
PercentageProblem p = (PercentageProblem)subject.GenerateQuestion(generator.Difficulty);
var isCorrect = false;
while (!isCorrect)
{
// Ask question
p.PrintQuestion(currentQuestion);
// Get answer
Console.Write("Answer: ");
int answer = 0;
bool validAnswer = true;
try
{
answer = Convert.ToInt32(Console.ReadLine());
}
catch (Exception)
{
validAnswer = false;
}
// Work out if answer is correct
if (validAnswer)
{
isCorrect = subject.IsCorrect(p, answer);
Console.WriteLine(isCorrect ? "Correct!" : "Not quite right. Try again.");
}
}
currentQuestion++;
}
}