Scope and Local Variables

• In general a block of code is code within { }
• Variables declared within a block of code are local to that block.
• The lifetime of a variable is the time it has memory allocated to it.
• All variables we have been dealing with are automatic variables. These variables are allocated at block entry and dealocated when the block exits.
• Static variables are variables that persist over invoctions of a block.
• The scope of a variable is the reagon of code where it is leagle reference that variable.
• A nonlocal identifier is in identifier that is declared outside of the scope of a block
• Some Rules
  1. Functions have global scope .. they can be used anywhere after they are declared
  2. Function parameters have scope in the outermost block of the function
  3. Scope of global variables or constants is for the entire program
  4. Scope of local variables extens over the block in which it is declared
  5. Local variables take persidence over global variables
• DO NOT USE GLOBAL VARIABLES.