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C# Intermediate C# Abstraction Abstract Members

In this challenge, I need to change SequenceDetector.Scan to an abstract method.

I have tried to make it so that the SequenceDetector.Scan had abstract before it, and it did not work! What am I missing?

RepeatDetector.cs
namespace Treehouse.CodeChallenges
{
    public class RepeatDetector : SequenceDetector
    {
        public override string Description => "Detects repetitions";

        public override bool Scan(int[] sequence)
        {
            LastScannedSequence = sequence;

            if(sequence.Length < 2)
            {
                return false;
            }

            for(int i = 1; i < sequence.Length; ++i)
            {
                if(sequence[i] == sequence[i-1])
                {
                    return true;
                }
            }

            return false;
        }
    }
}
SequenceDetector.cs
namespace Treehouse.CodeChallenges
{
    public abstract class SequenceDetector
    {
        public virtual string Description => "";

        public int[] LastScannedSequence { get; protected set; }

        public virtual bool Scan(int[] sequence)
        {
            LastScannedSequence = sequence;
            return true;
        }
    }
}

1 Answer

Allan Clark
Allan Clark
10,810 Points

I'm not sure what the error was as this is the base code from the challenge (my best guess is you may have left code inside the abstract method).

To change SequenceDetector.Scan to abstract you should just need to change the 'virtual' keyword to 'abstract' and delete the code inside the method so that it is just a method signature. In the end it should look like this:

public abstract bool Scan(int[] sequence);

Thanks so much!