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C# Intermediate C# Polymorphism Virtual Properties

Posted by Roger Sullivan
Roger Sullivan
10,992 Points

code wont compile, i literally copied and pasted then added override.

it says to look at the errors but output isn't even an option. also could you point me to where you guys explained the use of the lambda operator here? i need a refresher.

RepeatDetector.cs 
namespace Treehouse.CodeChallenges
{
    class RepeatDetector : SequenceDetector
    {

        public override string Description => "Detects repetitions";
        public override bool Scan(int[] 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
{
    class SequenceDetector
    {
        public string Description => "";

        public virtual bool Scan(int[] sequence)
        {
            return true;
        }
    }
}

2 Answers

andren
andren
28,558 Points
andren
andren
28,558 Points

By "Lambda operator" I assume you are referring to the => used in the Description property.

While it looks a bit like a lambda expression (which C# does support) it is actually not. It is an example of Expression-bodied members. Which is syntactic sugar built into C# that allows you to succinctly declare things like methods, property getters/setters, and constructors that fit one a single line.

The video where this concept was introduced was the Expression Bodied Members lecture in the C# Objects course.

Roger Sullivan
Roger Sullivan
10,992 Points

Great! Thank you, I had to take a bit of a deviation on my learning over to python so I forgot a few things.

Roger Sullivan
Roger Sullivan
10,992 Points
Roger Sullivan
Roger Sullivan
10,992 Points

I forgot the word "virtual", id still like a pointer to where they explain the lambda operator though.