Local Variables and Parameters Passed by Value

Local variables are very similar to parameters passed by value. Both have storage can change their values as the program executes. The only differences between a local variable and a parameter passed by value are the syntax of their definition and that a parameter passed by value has an initial value determined by the caller of the subroutine. A local variable does not have any initial value. As a result, it is important for a programmer to initialize a local variable before using its value.

Just like parameters, local variables are ``destroyed'' when a subroutine completes. This means the value of a local variable is not preserved across invocations.