Question

Create public class in C# such that following conditions are satisfied :

1. The class cannot be instantiated.
2. A function from that class can be called by other class.

I tried this way :

public abstract class A {

  public static void fun()
{
// do process.
}

}


public class B : A
{
// Now A can't be instantiated being abstract.
// And you can call its function like this :
A.fun();
}

But my answer was wrong.So, please help me out.

Answer 1

You can create a class like as follows to meet your goal

    public class A
        {
            private A()
            {           
            }

            public static A GetA()
            {
                return new A();
            }

              public void Foo()
              {}
        }

        public class B
        {
            public void Foo2()
            {
                A a = A.GetA();
                       a.Foo();
            }
        }

Making the constructor of A private would bar it from instantiating from another class. And the static method GetA will return an object of A instatiating it privately which you can use from any class.