R) Memory Management

Stack and heap

’new’ operator ??????????

Problems related with dynamic memory allocation

• accessing out-of-bounds memory
• dangling pointer
• double deleting
• null pointer dereference
• freeing memory blocks that were not dynamically allocated
• attempting to free a portion of a dynamic block
• memory leak

Stack vs Heap

• Stack
  • very fast access
  • space is managed efficiently by CPU,
  • memory will not become fragmented
  • limit on stack size (OS-dependent)
• Heap
  • no limit on memory size
  • slower access
  • memory may become fragmented
  • you must manage memory (you’re in charge of allocating and freeingvariables)

Memory management

Implicit (automatic) memory management:

• garbage collector
  • mark and sweep
  • reference counting

In C++ there is no automatic memory management.

Explicit memory management:

• RAII
• smart pointers (which implements RAII)