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C# Intermediate C# Polymorphism Accessor Access Modifiers

Jack Lee
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.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
216,083 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.