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 chanjong kim
chanjong kim
2,315 Points

I have no idea why it keeps showing error

HI, I am working on overriding the Scan method in RepeatDetector.cs that should return 'true' when a value in array is the same with immediately preceding it.

in for loop, if(sequence[i]==sequence[i-1]) { return true; break; }

is what I wrote and i think it makes sense. could you help me to find why it throws compiler error?

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;
                    break;
               }
            }
        }
    }

}

1 Answer

Steven Parker
Steven Parker
229,732 Points
Steven Parker
Steven Parker
229,732 Points

If no repeat is found, the method ends without returning anything. But it is declared as returning a bool. So you'll need a "return false;" after the loop ends.

Also, you don't need the "break" since nothing after a "return" will ever be executed.