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C# Intermediate C# Abstraction Interfaces

whats wrong here ?

whats is done wrong here it gives me a compiler error

IUnaryOperation.cs
namespace Treehouse.CodeChallenges
{
    interface IUnaryOperation
    {
        double Perform(double value);
    }

}
Increment.cs
namespace Treehouse.CodeChallenges
{
    class Increment : IUnaryOperation
    {
       double Perform(double value)
       {
            return value += 1;
       }
    }

}

1 Answer

Jennifer Nordell
seal-mask
STAFF
.a{fill-rule:evenodd;}techdegree
Jennifer Nordell
Treehouse Teacher

Hi there, AbduRahman Ezzeldin! The problem here is that your implementation of the method was not made public so it can't be accessed even though it's there. You would have to make the method of that class public so instead of:

class Increment : IUnaryOperation
    {
       double Perform(double value)
       {
            return value += 1;
       }
    }

You would need:

class Increment : IUnaryOperation
    {
       public double Perform(double value)  // this must be public
       {
            return value += 1;
       }
    }

Hope this helps! :sparkles: