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C# C# Objects Encapsulation with Properties Computed Properties

viktor Degerman
viktor Degerman
3,056 Points
Posted by viktor Degerman
viktor Degerman
3,056 Points

What is wrong with this code??

I dont understand what i have done wrong help

Square.cs 
namespace Treehouse.CodeChallenges
{
    class Square : Polygon
    {   
        public double SideLength { get; private set; }

        public Square(double sideLength) : base(4)
        {
            SideLength = sideLength;
            Area = SideLength * SideLength;
        }

        public double Area 
        {
            get
            {
                return Area;
            }
        }
    }
}
Polygon.cs 
namespace Treehouse.CodeChallenges
{
    public class Polygon
    {
        public int NumSides { get; private set; }

        public Polygon(int numSides)
        {
            NumSides = numSides;
        }
    }
}

1 Answer

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

The point of a computer property is that it's value is calculated at the moment the get method is called, with your code it simply returns a value that is computed when the class is constructed. Also setting Area in the construct won't actually work because Area is a read-only property since it has no setter method.

You can fix both of those errors by simply moving the computation that you stored in the Area property in the constructor to the return statement of the get method like this:

namespace Treehouse.CodeChallenges
{
    class Square : Polygon
    {   
        public double SideLength { get; private set; }

        public Square(double sideLength) : base(4)
        {
            SideLength = sideLength;
        }

        public double Area 
        {
            get
            {
                return SideLength * SideLength;
            }
        }
    }
}