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 Accessor Access Modifiers

Jack Lee
seal-mask
.a{fill-rule:evenodd;}techdegree
Jack Lee
Full Stack JavaScript Techdegree Student 15,536 Points
Posted by Jack Lee
.a{fill-rule:evenodd;}techdegree
Jack Lee
Full Stack JavaScript Techdegree Student 15,536 Points

Error "Did you declare $ property with the 'public' access modifier?" when declared as protected

Referenced protected member is on Line 7

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

        protected int[] LastScannedSequence { get; set; }

        public virtual bool Scan(int[] sequence)
        {
            LastScannedSequence = sequence;
            return true;
        }
    }
}
RepeatDetector.cs 
namespace Treehouse.CodeChallenges
{
    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;
        }
    }
}

1 Answer

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

You need two different access modifiers.

One for the property as a whole, and one just for the set capability.

The challenge says "Other classes should still be able to get the last scanned sequence." But that would not be possible if you set the property to protected. To allow other classes to get it, it must be public.

But the instructions also say, "only SequenceDetector and its subclasses can set the... property". So what you want protected is the property's set method.