Question

I am writing following code,

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace ReadOnlyObject
{
    class Program
    {
        private readonly int a = 20;
        private readonly int b;
        public int propa{get;private set;}

        public int propb { get; private set; }

        public Program(int tmp)
        {
                   b = tmp;
        }
        static void Main(string[] args)
        {
                   Program obj1 = new Program(30);

                   Console.WriteLine(obj1.propa);        // Console.WriteLine(obj1.a);

                   Console.WriteLine(obj1.propb);        // Console.WriteLine(obj1.b);

                   Console.Read();
        }
    }
}

After executing the above i got o/p as follows,

0
0

And when I change the code by replacing two commented statements printing direct member variables I got output as,

20
30

Why is so?
As far I know about properties they are associated with their definition in order the member variables are declared.

Answer 1

There are two ways to define properties in C#.

The first, the traditional way;

int myProperty;

public int MyProperty 
{
  get { return myProperty; }
  set { myProperty = value; }
}

the second, the auto-property;

   public int MyProperty {get;set;}

The first contains a backing variable that you reference in the property accessor. The second implicitly creates a backing variable, because the developers of the language understood that there are a lot of cases where you just need a property!

You can put scope on the auto-property, because you might want to prevent people from setting the value, but internally to the object you should be able to update the value of it.

“As far I know about properties they are associated with their
defination in order the member variables are declated.”

Just to clarify all of what you were asking, unless I am reading this statement incorrectly, you’re thinking that if you declare variable a and b and the property a and property b that they’ll be associated. This is an incorrect assumption.