W8013 Possible use of 'identifier' before definition (C++)
(Command-line option to display warning: -wdef)
Your source file used the variable 'identifier' in an expression before it was assigned a value.
The compiler uses a simple scan of the program to determine this condition.
If the use of a variable occurs physically before any assignment, this warning will be generated.
Of course, the actual flow of the program can assign the value before the program uses it.