I have also created a small video explaining the private constructor. Do visit my 21 important .NET interview questions and answers.

Answer:

This is one of those .NET interview question which is asked from the perspective to test if you understand the importance of private constructors in a class.

When we declare a class constructor as private , we can not do 2 things:-

• We can not create a object of the class.
• We can not inherit the class.

Now the next question which the interviewer will ask , whats the use of such kind of class which can not be inherited neither instantiated.

Many times we do not want to create instances of certain classes like utility , common routine classes. Rather than calling as shown below 

clsCommon common = new clsCommon();
common.CheckDate("1/1/2011");

You would like to call it as

clsCommon.CheckDate("1/1/2011");

Check my 21 important .NET interview questions and answers