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3. Stack, local variables and static locals

09/02/23

Stack​

  • Stack is LIFO
  • Function calls (Stack frames) are store on a stack in memory
  • Most stacks go down in memory address
  • Values are stored together in the stack frame

Lifetime of a local variables​

  • Local variables exist for the duration of the stack frame they are in
  • They get destroyed; if you use malloc() you need to call free()

⚠️DANGER⚠️​

  • Your local variables only exist for as long as the block in which they are defined.
  • Do not access them after that
  • Do not assume that they keep their value after the function ends

Global and static local variables​

Global Variables​

  • Variables are declared outside of all functions and last for the duration of the program
  • All functions in the file can access goals
  • Can be hidden from other files

Local Variables​

  • Can be static
    • Means not moving/unchanging
    • NOT the same as static member variables
    • NOT the same as const
  • Static local variables remember their value between function calls