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Is using var actually slow? If so, why?

I learn C # and .NET, and I often use the keyword varin my code. I got an idea from Eric Lippert, and I like how this improves my code performance.

I’m curious, though ... a lot has been written on blogs about slow heap links, but I don’t observe this myself. Is it really slow? I mean slow compilation time due to type input.

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5 answers

You declare:

I mean slow compilation time due to type 'inferencing'

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; , # ( ).

... .

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'var' # VARIANT, VB. var - , . . - , :

var x = new X();

,

X x = new X();

, . , "" (, ) .

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Var . dynamic?

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"" "", ( ) : (1) "" (2) "" .

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If you are talking about " var", then this is just a convenient way to tell you: "Compiler, enter the correct type here" because you do not want to do this work, and the compiler should be able to understand this. In this case, " var" does not constitute an "execution option", but rather the syntax of the source code specification.

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The compiler infers the type from the constructor.

var myString = "123"; no different from string myString = "123";

Also, generally speaking, reference types live in heap types and values ​​that are on the stack, regardless of whether they are declared using var.

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