Why do we need a private constructor?

Question

If a class has a private constructor then it can\'t be instantiated. So, if I don\'t want my class to be instantiated and still use it, then I can make it static.

Wh

Answer 1

Purpose to create the private constructor within a class

1. To restrict a class being inherited.

2. Restrict a class being instantiate or creating multiple instance/object.

3. To achieve the singleton design pattern.

   public class TestPrivateConstructor
   {
       private TestPrivateConstructor()
       {  }
   
       public static int sum(int a , int b)
       {
           return a + b;
       }
   }
   
   class Program
   {
       static void Main(string[] args)
       {
           // calling the private constructor using class name directly 
           int result = TestPrivateConstructor.sum(10, 15);
           // TestPrivateConstructor objClass = new TestPrivateConstructor(); // Will throw the error. We cann't create object of this class
       }
   }