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C# Intermediate C# Abstraction Abstract Members

Posted by shawn khah
shawn khah
15,082 Points

can't solve challenge 1 of 1

Challenge Task 1 of 1

Change SequenceDetector.Scan to an abstract method. Important: In each task of this code challenge, the code you write should be added to the code from the previous task. Restart Preview Get Help Check 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 virtual 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 virtual bool Scan(int[] sequence)
        {
            LastScannedSequence = sequence;
            return true;
        }
    }
}

1 Answer

Seth Kroger
Seth Kroger
56,413 Points
Seth Kroger
Seth Kroger
56,413 Points

OK, so you're asked to change Scan() to an abstract method. Scan is currently a virtual method. Abstract methods are a lot like virtual methods, but the big difference is they don't have method bodies. So to do this challenge you need to 1) change virtual to abstract and 2) remove the code for Scan and replace it with a semi-colon at the end of the method declaration.

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

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

        public abstract bool Scan(int[] sequence);
    }
}
shawn khah
shawn khah
15,082 Points

thank's seth