Question

Consider the declarations

Dim x As Double
Dim avg(1 To 10) As Double

What are the default values in x and avg?

Through testing, I want to say that x is initialized to zero.
Likewise, I want to say that all elements in avg were initialized to zero.

However, can I write code that depends on this? Or are the default initialization values actually indeterminate?

Answer 1

If you specify a data type but do not specify an initializer, Visual Basic initializes the variable to the default value for its data type, which for all numeric types is 0 (zero).

When you run a macro, all the variables are initialized to a value. A
numeric variable is initialized to zero, a variable length string is
initialized to a zero-length string (""), and a fixed length string is
filled with the ASCII code 0. Variant variables are initialized to
Empty. An Empty variable is represented by a zero in a numeric context
and a zero-length string ("") in a string context.

Ref. Link dead.

Instead: How to use variables in Excel sub-procedures in Visual Basic for Applications