Automatic variable
In computer programming, an automatic variable is a lexically-scoped variable which is allocated and deallocated automatically when program flow enters and leaves the variable's scope. The term local variable is usually synonymous with automatic variable, since these are the same thing in many programming languages.
Automatic variables may be allocated in the stack frame of the procedure in which they are declared; this has the useful effect of allowing recursion and re-entrancy. (For efficiency, the optimizer will try to allocate some of these variables in processor registers.)
