Iterators allow a uniform way to travel through all STL containers.


#include <iostream>

#include <list>



int main()

{

  std::list<int> my_list;

  my_list.push_back( 1);

  my_list.push_back( 4);

  my_list.push_back( 9);

  my_list.push_back(16);

  my_list.push_back(25);

  my_list.push_back(36);

  my_list.push_back(49);



  //Display the list (not preferred)

  typedef std::list<int>::const_iterator Iterator;

  const Iterator j = my_list.end();

  for (Iterator i = my_list.begin(); i!=j; ++i)

  {

    std::cout << *i << '\n';

  }

}

Screen output:

Note the following about the code shown above:

The preferred way to display the contents of the list can be found at the CoutContainer code snippet. Prefer using standard algorithms, instead of crafting your own for loops [1].
std::list<int>::const_iterator was used, instead of std::list<int>::iterator. Use const_iterator when you are not modifying the contents of a container [2].
operator!= was used instead of operator<. Prefer comparing iterators with operator!=, instead of operator< [3].
The prefix form of operator++ was used (that is '++i' instead of 'i++'). Prefer using the prefix form, unless you really need the old value [4].

References

Herb Sutter. Exceptional C++ style. 2005. ISBN: 0-201-76042-8. Item 1 guideline: 'Prefer reusing algorithms, particularly standard algorithms (e.g., for_each), instead of crafting your own loops'.
Herb Sutter. Exceptional C++ style. 2005. ISBN: 0-201-76042-8. Item 1 guideline: 'Use const_iterator when you are not modifying the contents of a container'.
Herb Sutter. Exceptional C++ style. 2005. ISBN: 0-201-76042-8. Item 1 guideline: 'Prefer comparing iterators with !=, not <'.
Herb Sutter. Exceptional C++ style. 2005. ISBN: 0-201-76042-8. Item 1 guideline: 'Get in the habit of using the prefix forms of -- and ++ by default, unless you really need the old value'.

Go back to Richel Bilderbeek's C++ page.

Go back to Richel Bilderbeek's homepage.

(C++) Iterator

References