help the beginner (value null)

[sergey7777777]

Dim a, b As Int

If a = null Then ' not work b4a
b=100
End If

Msgbox (b, "I want 100")

prompt a condition that earned...
forgive I a beginner

 

[Erel]

An Int variable cannot be null. The value of a newly declared int is 0.

 

[sergey7777777]

thanks for movement top
I didn't find this section:sign0188:

What to do if to a condition the variable doesn't exist?

 

[Erel]

What to do if to a condition the variable doesn't exist?

Can you give an example?