The uses of pointers:

• indirect addressing
• dynamic storage management

char InputChar = 'A';
char *ptrchar;
ptrchar = &InputChar;

In the above statements:
    1) InputChar is bound to a memory block with 'A' in it.
    2) ptrchar is declared as a pointer and bound to a random block.
    3) The address of InputChar is put into the block that ptrchar is bound to.

• What are the scope and lifetime of a pointer variable?
• What is the lifetime of a heap-dynamic variable?
• Are pointers restricted as to the type of value to which they can point?  (Is type of value retricted?)
• Are pointers used for dynamic storage management, indirect addressing or both?
• Should the language support pointer types, reference types, or both?

• assignment:
  • pointer variable's value = some useful address
• dereferencing (see Figure 6.8)      j = *ptr
   
• The value stored at the address in the pointer memory block is returned
  • e.g.    In the example above, the computer would go to ptrchar's memory block and
    find the address of InputChar.  Then it would go to that address and return whatever
    is there ('A').

• Dangling Pointers:   Pointer points to heap-dynamic variable that has deallocated.
• e.g.

1) ptr1 is set to new heap-dynamic variable
2) ptr2 = ptr1
3) ptr1 = nil,(deallocate), ptr2 is dangling.
• eg.
  int * ptr1 = new int(7);
  int * ptr2 = ptr1;
  delete ptr1;    //deallocate the heap variable
  The ptr2 is dangling.
• Lost Heap Variables:  An allocated heap-dynamic variable is no longer accessible to the user program.
• e.g.

1) ptr1 is set to new heap-dynamic variable
2) ptr1 gets set to another new heap-dynamic variable
The first new heap-dynamic variable is now inaccessible, or lost.
This problem is also called memory leakage.
• eg.
  int * ptr1 = new int (7);
  ptr1 = new int(100);
  The heap variable with 7 is lost and no one points to it.