B4J Question Are variables automatically initialized?

LucaMs

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• Sep 24, 2018

• #2

I think yes (just a very little doubt about "a" in myType).

But... you can try spending 2 seconds, using just a simple Log

 

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Daestrum

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• Sep 24, 2018

• #3

The 'a' in the dim statement is not the same as the 'a' in the type statement.

If the dim and type statements are in Process_Globals then

The type statement creates a java class containing the field named 'a' which is only guaranteed to be 0 after the initialize method is called.

B4X:

  public static class _mytype
  {
    public boolean IsInitialized;
    public int a;
  
    public void Initialize()
    {
      this.IsInitialized = true;
      this.a = 0;
    }

The dim statement creates a java variable called '_a' which is set to 0.

B4X:

  public static int _a = 0;

 

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MarkusR

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• Sep 24, 2018

• #4

erel wrote only b4r did not initialized primitive datatype variables.
its also special that u not need to initialize a Type, its automatical.

 

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A

Alessandra Pellegri

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• Sep 25, 2018

• #5

Thank you guys.

In effect looking at myType.initialize tip: it says that it put all variables to their default value. So for structures isn't automatic, I have to initialize.

 

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MarkusR

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• Sep 25, 2018

• #6

from generated source code i would agree that u need to use .initialize for a structur class.
but for any reason the integer inside have 0 as default value without the usage of initialize.

 

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A

Alessandra Pellegri

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• Sep 25, 2018

• #7

MarkusR said:

from generated source code i would agree that u need to use .initialize for a structur class.
but for any reason the integer inside have 0 as default value without the usage of initialize.

Click to expand...

I think that the reason is that when you turn on the PC, all registers are zeros. So if a dram cell isn't still used until that moment, the related variable is zero. But you cannot be sure.

 

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