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I'm reviewing an automatic translation of VB6 code to C# and the convertor translated someArray(3) to someArray[3]. But accordingly to the old code documentation it should pick the third element not the fourth as it is doing in the translated version.
Are array indexes 0-based in VB6? Or do they start at 1?
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All arrays must be zero-indexed. In Microsoft Visual Basic 6.0, you can define arrays with the lower bounds and upper bounds set to any integer. In Microsoft Visual Basic . NET, the lower bound of every array dimension is zero (0).
In computer science, array indices usually start at 0 in modern programming languages, so computer programmers might use zeroth in situations where others might use first, and so forth.
An array arr[i] is interpreted as *(arr+i). Here, arr denotes the address of the first array element or the 0 index element. So *(arr+i) means the element at i distance from the first element of the array. So array index starts from 0 as initially i is 0 which means the first element of the array.
Zero-based array indexing is a way of numbering the items in an array such that the first item of it has an index of 0, whereas a one-based array indexed array has its first item indexed as 1. Zero-based indexing is a very common way to number items in a sequence in today's modern mathematical notation.
Yes - arrays are (generally) 0 based in VB6
The exceptions to this are when the explicit Dim someArray(1 To 10) as Int syntax has been used, or when Option Base 1 is declared at the top of the code module.
It's Collections that aren't - when you loop through Collection objects I'm pretty sure that they are 1 based.
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The short answer is that array lower bounds are what you tell them to be.
The default is base 0 (unless overridden by Option Base 1), but you can declare lower bound to any value you want (Dim arr(-42 To 42) is as valid as Dim(3)).
Also, if an array is returned by some object, its lower bound is whatever that object sets it to. For example an Excel Range.Value reference will return a 1 based array.
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