The lifetime of local variables

When a method or function is called, control passes to that method or function.

The local variables belonging to that method or function come into existence at that point. 

They can be used while control remains in the method or function.

However, they cease to exist and become unavailable for use when control exits that method or function.

Therefore, local variables can't be used to carry data forward from one method call to the next call to the same method.