Why use var instead of the class name? [duplicate]

Question

Possible Duplicate:
What's the point of the var keyword?
What advantages does using var have over the explicit type in C#?

I always see other people producing code like:

var smtp = new SmtpClient();

But why use var instead of SmtpClient in this case? I ALWAYS use

SmtpClient smtp = new SmtpClient();

Is var more efficient? Why use var instead of the actual variable type? Am I missing something?

Answer 1

Imagine this.

Dictionary<Dictionary<String, String>, String> items = new Dictionary<Dictionary<String, String>, String>();

var is useful for things like that.

var items = new Dictionary<Dictionary<String, String>, String>();

Much simpler. The point of var is the same as auto in C++ 11, the compiler knows the type so why must we repeat ourselves so much. I personally use var rarely, but only for lengthly declarations. It's just syntactic sugar.

Answer 2

No it isn't more efficient. It's the same thing of write explicitly the type. Infact it is good programming write the type of the variable instead of use var because it makes the code more readable.

So:

var smtp = new SmtpClient();

And:

SmtpClient smtp = new SmtpClient();

Are the same thing wrote in two different ways.