Welcome to the Treehouse Community

Want to collaborate on code errors? Have bugs you need feedback on? Looking for an extra set of eyes on your latest project? Get support with fellow developers, designers, and programmers of all backgrounds and skill levels here with the Treehouse Community! While you're at it, check out some resources Treehouse students have shared here.

Looking to learn something new?

Treehouse offers a seven day free trial for new students. Get access to thousands of hours of content and join thousands of Treehouse students and alumni in the community today.

Start your free trial

C# Intermediate C# Abstraction Abstract Members

help plz

Challenge Task 1 of 1

Change SequenceDetector.Scan to an abstract method. Bummer! Your code could not be compiled. Please click on "Preview" to view the compiler errors. Restart Preview Get Help Recheck work RepeatDetector.cs SequenceDetector.cs

; 1 namespace Treehouse.CodeChallenges 2 { 3 public abstract class SequenceDetector 4 { 5 public virtual string Description => ""; 6 ā€‹ 7 public int[] LastScannedSequence { get; protected set; } 8 ā€‹ 9 public abstract bool Scan(int[] sequence); 10 { 11 LastScannedSequence = sequence; 12 return true; 13 } 14 } 15 } 16 ā€‹

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

2 Answers

Seth Kroger
Seth Kroger
56,413 Points

Abstract methods can't have a method body. If you remove the old method body it will pass the challenge.

Geovanie Alvarez
Geovanie Alvarez
21,500 Points

In the SequenceDetector class in the scan method just remove the method body.

{
    LastScannedSequence = sequence;
    return true;
}