C# private class without nesting in parent class -

is possible in c# define private class without nesting in parent class? below simplified example of i'm trying do

public abstract class classa<t>  {     public t value { get; set; }      public classa(t value)     {         value = value;     } }  private class classb : classa<int> {     public classb(int value)          : base(value)     {     } } 

i'd classb accessible classa. i'm wondering if i'm trying possible if 2 classes in same file. basically, nice hide extensions of classa, i'd rather not nest many classes.

what purpose of having private class on own? won't able reference class. private classes possible inside classes because outer class can access it.