It's possible to use variables for more than one purpose in several subtle ways. You're better off without this kind of subtlety.
Use each variable for one purpose only. It's sometimes tempting to use one variable in two different places for two different activities. Usually, the variable is named inappropriately for one of its uses or a "temporary" variable is used in both cases (with the usual unhelpful name x or temp). Here's an example that shows a temporary variable that's used for two purposes: