Does it make any practical difference to instantiate an object inside the constructor?

Question

Is there any practical difference between those two ways of instantiating an object?

public class myClass
{
   private myType myObject = new myType();

}

and

public class myClass
{
   private myType myObject;

   public myClass()
   {
       myObject = new myType();
   }

}

Thanks for helping.

It is the *exact* same code. Easy to see with a disassembler like ildasm.exe — Hans Passant, Jun 09 '14 at 21:22
Introduce a base class (actually, there already is one... `Object`). Initializing your fields inside or outside the constructor changes the order in which they are initialized. — Anthony Pegram, Jun 09 '14 at 21:30
For more on my prior comment, see [this answer](http://stackoverflow.com/a/7109564/414076) (that links over to Eric Lippert's blog) — Anthony Pegram, Jun 09 '14 at 21:32

score 0 · Answer 1 · answered Jun 09 '14 at 21:22

0

No there isn't any practical difference, between the two ways you provided. They are exaclty the same.

answered Jun 09 '14 at 21:22

Christos

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score 0 · Answer 2 · answered Jun 09 '14 at 21:27

0

The answer is yes

When you read the code later, you will look in the constructor to see what happens when you create the class. If you put constructor logic outside the constructor another developer may miss what's going on. So put your constructor logic in your constructor. It makes a difference.

answered Jun 09 '14 at 21:27

Niels Brinch

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You are talking about readability, OP is asking about differences in object instansiation – Yuval Itzchakov Jun 09 '14 at 21:30
1

Moreover, I would imagine that if you asked 100 programmers which style they prefer, you would get a pretty even split. It definitely isn't black and white. – BradleyDotNET Jun 09 '14 at 21:32

score 0 · Answer 3 · answered Jun 09 '14 at 21:32

As far as the code goes, there isn't much difference. Initialization in the declaration happens in document order, top to bottom, which might or might not have side effects. From a practical perspective, if you do any interactive debugging at all, you'll grow to hate declaration initializations, unless you enjoy stepping through them one at a time.

Keep your code tidy and initialize things in the constructors.

Does it make any practical difference to instantiate an object inside the constructor?

3 Answers3