one line struct initialization

[Zytan]

Is it possible, as in C? I don't think it is. Just checking.

Zytan

[Mattias Sjögren]

>Is it possible, as in C? I don't think it is. Just checking.

If you provide a constructor that will initialize all members.
Mattias

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[Chris Nahr]

On 6 Mar 2007 20:03:39 -0800, "Zytan" <zy**********@y ahoo.comwrote:

>Is it possible, as in C? I don't think it is. Just checking.

Why wouldn't it be possible? What exactly are you referring to?
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[Zytan]

Is it possible, as in C? I don't think it is. Just checking.

>
Why wouldn't it be possible? What exactly are you referring to?

I mean like so:

int x = 4; // declared and initialized in one line

struct abc { ... };
abc = ...; // declared and initialized in one line. Is this possible?

Zytan

[Zytan]

Is it possible, as in C? I don't think it is. Just checking.

>
If you provide a constructor that will initialize all members.

I wasn't looking to use a constructor. But, maybe I need one.
Does "int x = 4;" invoke a constructor for 'int'? Is that how
declarations and initializations are done on the same line?

Zytan

[Zytan]

struct abc { ... };

abc = ...; // declared and initialized in one line. Is this possible?

Oops, I mean:

struct abc { ... };
abc y = ...; // declared and initialized in one line. Is this
possible?

Zytan

[Mattias Sjögren]

>I wasn't looking to use a constructor. But, maybe I need one.

Well maybe you can get by with an implicit conversion operator
instead. It depends on what kind of expression you want on the right
hand side of the assignment.

One way or another the RHS expression must be turned into an instance
of your struct.

>Does "int x = 4;" invoke a constructor for 'int'?

No, but int in special since you can write literals for it in C# and
there are special IL opcodes for it.
Mattias

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[Jon Skeet [C# MVP]]

Zytan <zy**********@y ahoo.comwrote:

>Is it possible, as in C? I don't think it is. Just checking.

If you provide a constructor that will initialize all members.

I wasn't looking to use a constructor. But, maybe I need one.
Does "int x = 4;" invoke a constructor for 'int'? Is that how
declarations and initializations are done on the same line?

Well, the primitive types are a special case - but yes, if you want to
initialize a struct, you generally need to call a constructor. If it's
a mutable struct (generally a bad idea) you *could* just do:

MyStruct x;
x.SomeProperty = ...;

but it's generally better to have a constructor which fully constructs
the struct, and call that.

--
Jon Skeet - <sk***@pobox.co m>
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If replying to the group, please do not mail me too

[Zytan]

Well maybe you can get by with an implicit conversion operator

instead. It depends on what kind of expression you want on the right
hand side of the assignment.

One way or another the RHS expression must be turned into an instance
of your struct.

Yes, it sounds like using a constructor is the proper way, then.

Does "int x = 4;" invoke a constructor for 'int'?

No, but int in special since you can write literals for it in C# and
there are special IL opcodes for it.

Right, that's what I thought.

Zytan

[Zytan]

Well, the primitive types are a special case - but yes, if you want to

initialize a struct, you generally need to call a constructor.

I guess I was just looking for something as simple as what you can do
with initializing an array:

int[] x = new int[] { 4, 5, 6, 7 };

If it's
a mutable struct (generally a bad idea) you *could* just do:

MyStruct x;
x.SomeProperty = ...;

but it's generally better to have a constructor which fully constructs
the struct, and call that.

Yes, I think I need a constructor. I did notice that C# complains if
you only initialize a portion of the fields in the struct (if you miss
one) and then attempt to use it. So, it is safe (perhaps not so in
earlier versions?). But, a c'tor seems more safe.

A mutable struct is a bad idea? What is a mutable struct? I know
mutable means it can change. But, unless all fields are private,
isn't the struct mutable? Or is this precisely what you mean, that
struct fields should all be private (almost like a class)?

Zytan