VB.net processes Variable Allocation and initialization in a loop

The following two paragraphs Code What output will each have:
1.
For I as integer = 0 to 3
Dim J as integer = 10
Debug. writeline (j)
J + = 1
Next
2.
For I as integer = 0 to 3
Dim J as integer
Debug. writeline (j)
J + = 1
Next

The answer is:
1.
10
10
10
10
2.
0
1
2
3
Through the above example, we can guess that the way VB.net processes the variable in the loop is: one allocation. If there is an initialization value, the initialization value will be assigned to each loop, otherwise, the initial value is (memory) 0 at the first allocation.
This also shows that the variable in the loop is not equivalent to the variable in the same defined function range.
Therefore, if you want to avoid the effect of keeping changes like code 2, you should specify the reason why the variable should be initialized at the beginning of the loop.