C# Online Compiler | .NET Fiddle

        using System;  
  
        public class Addition  
        {  
            int a, b; 
			//default contructor  
            public Addition()   
            {  
                a = 100;  
                b = 175;  
            }  
       
            public static void Main()  
            {  
                Addition obj = new Addition(); //an object is created , constructor is called here 
                Console.WriteLine(obj.a);  
                Console.WriteLine(obj.b);  
                 
            }  
        }

 
        using System;  
  
        public class Addition  
        {  
            int a, b; 
            //default contructor  
            public Addition()   
            {  
                a = 100;  
                b = 175;  
            }  
       
            public static void Main()  
            {  
                Addition obj = new Addition(); //an object is created , constructor is called here 
                Console.WriteLine(obj.a);  
                Console.WriteLine(obj.b);  
                 
            }  
        }  
    
​

Unhandled exception. System.ArgumentOutOfRangeException: Index was out of range. Must be non-negative and less than the size of the collection. (Parameter 'index')
at System.Collections.Generic.List`1.get_Item(Int32 index)
at Program.Main()
Command terminated by signal 6