C# property getter and setter implementation

Question

What is the difference between the implementation of

Class cl1
{
    public int var{get;set;}
}

and

Class cl1
{
    public int var;
}

I mean, both are implemented like this -

void Main()
{
    cl1 obj = new cl1();
    obj.var = 25;
    int k = obj.var;
}

and if there is no difference, then why do I see the 2nd implementation so common in Library Assemblies??

Answer 1

I think about two reason:

1. it hide the implementation: property var may use a private field which isn't a var or may not use a private field at all and the client will not know this

2. It's easier to change: if in your code you use field obj.var 100 times and at some point you must change something of that field you have to modify all the calls, while if you have a property you can modify the implementation in a simpler way without having to modify all the call (at least if you don't change the signature of the property)

probably other reason that doesn't come to my mind now