Android Question Initial state of variables

Paulo Rosa · Sep 6, 2018

Hi,

Just a small doubt I couldn't find the answer for in B4X documentation:

In VB 6 variables are always initialized when they are declared. For instance, if I declare "Public myflag as boolean", I can be sure that myflag variable will have the initial state of false... and so on for the other types of variables (zero for numeric types, empty string for strings, etc.).

Do B4A, B4J, etc. have the same behaviour? Can I always assume that variables are initialized with their default values, at the moment they are declared?

Regards,

LucaMs · Sep 8, 2018

This is because Items is an array, not a simple variable of "simple" type.

Cableguy · Sep 8, 2018

LucaMs said:
This is because Items is an array, not a simple variable of "simple" type.

No, it's because items is a field of a type and the Type object must be initialized

Cableguy · Sep 8, 2018

And stop making me hungry!

LucaMs · Sep 8, 2018

Cableguy said:
No, it's because items is a field of a type and the Type object must be initialized

Try this:

B4X:

' Process_Globals
Type MyType (Name As String, Item As Int)


Sub SomeRoutine

   Dim a As MyType
   a.Name = "even more angry"
   a.Item = 2
 
   Log(a.Name & TAB & a.Item)

MarkusR · Sep 8, 2018

@LucasMs
#24 that i meant there is a.IsInitialized=False but it can be used.
before i had this idea for you

B4X:

Type MyInt(Value As Int)

and thought it raised an error

LucaMs · Sep 8, 2018

Cableguy said:
And stop making me hungry!

Well, now I'm really hungry

Cableguy · Sep 8, 2018

LucaMs said:

Try this:

B4X:

' Process_Globals
Type MyType (Name As String, Item As Int)


Sub SomeRoutine

   Dim a As MyType
   a.Name = "even more angry"
   a.Item = 2
 
   Log(a.Name & TAB & a.Item)

Just because it works and raised no errors does not mean it's the correct way to do it!

LucaMs · Sep 8, 2018

Cableguy said:
Just because it works and raised no errors does not mean it's the correct way to do it!

In fact, absolutely not, it is much better to always initialize, even the normal variables for which it is not necessary; just what I mean.

MarkusR · Sep 8, 2018

@LucasMs
have a solution how about :
DimNotInitialized a as mytype
DimNotInitialized b as int

LucaMs · Sep 8, 2018

MarkusR said:
@LucasMs
have a solution how about :
DimNotInitialized a as mytype
DimNotInitialized b as int

Is it a suggetion for Erel?

MarkusR · Sep 8, 2018

@LucasMs
he will say no and maybe a compiler option DoNotInitialize is better.

LucaMs · Sep 8, 2018

MarkusR said:
a compiler option DoNotInitialize is better.

LucaMs · Sep 8, 2018

MarkusR said:
a compiler option DoNotInitialize is better.

Unfortunately I fear it is impossible.

Cableguy · Sep 8, 2018

The rolling stones were right...
You can't always get what you want!

LucaMs · Sep 8, 2018

Cableguy said:
The rolling stones were right...
You can't always get what you want!

Ok, but I do not pretend so much; just to be 30 again, 30 billion euros and Ornella Muti 20 years old, that's all, nothing more.

Android Question Initial state of variables

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