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# Polymorphism Virtual Methods

Posted by Stephen Callum
Stephen Callum
2,333 Points

RepeatDetector.Scan doesn't detect repetitions.

What am I missing here? Nothing looks wrong here to me. Unless TTH wants a specific implementation?

SequenceDetector.cs 
namespace Treehouse.CodeChallenges
{
    class SequenceDetector
    {
        public virtual bool Scan(int[] sequence)
        {
            return true;
        }
    }
}
RepeatDetector.cs 
namespace Treehouse.CodeChallenges
{
    class RepeatDetector : SequenceDetector
    {
        public override bool Scan(int[] sequence)
        {
            for(int i = 1; i < sequence.Length; i++)
            {
                if(sequence[i] == sequence[i]-1)
                {
                    return true;
                }
            }
            return false;
        }
    }
}

1 Answer

Steven Parker
Steven Parker
231,198 Points
Steven Parker
Steven Parker
231,198 Points

You're really close! But instead of decrementing the value of the indexed item, decrement the index instead so you can compare with the previous item:

//              if(sequence[i] == sequence[i]-1)   // original
                if (sequence[i] == sequence[i-1])  // fixed
Stephen Callum
Stephen Callum
2,333 Points

-_- Thanks... In the back of my mind I knew it was going to be something I did.