17. Reference examples

• 
  void swap( int& left, int& right )
  {
      int temp = left;
      left = right;
      right = temp;
  }
  
  void f()
  {
      int x = 8;
      int i = 4;
      int& ri = i;
      ++ri;          // now i == 5
      ri = x;        // now i == 8
      int& ref2 = 2; // error, RHS must be an lvalue
  }