Pointers and References

http://quiz.geeksforgeeks.org/commonly-asked-c-interview-questions-set-1/

Reference

Definition: A reference is another name for a pre-existing object and it does not have memory of its own. (for efficiency gaining)
Syntax:

int x;
int& foo = x;

• cannot be created without specifying where in memory it refers to.

Similarities

• change local variables inside another function.
• save copying of big objects when passed as arguments to functions or returned from functions, to get efficiency gain.

Diferences

References are less powerful than pointers

• Reference cannot be reseated.
• References cannot be NULL.
• Reference must be initialized when declared.
• References in C++ cannot be used for implementing data structures like Linked List, Tree, etc.

References are safer and easier to use:

• no wild reference as wild pointer.
• easier to use: References can be used like normal variables. ‘&’ operator is needed only at the time of declaration.
• access member of an object reference: '.' vs. '->'.

Notes

  int *p = new int;
  *p = 7;
  int *q = p;
  *p = 8;
  cout << *q << endl;
  // output 8

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