C++ Iterators

C++ Iterators

Iterators are used to access members of the container classes, and can be used in a similar manner to pointers. For example, one might use an iterator to step through the elements of a vector. There are several different types of iterators:

Each of the container classes is associated with a type of iterator, and each of the STL algorithms uses a certain type of iterator. For example, vectors are associated with random-access iterators, which means that they can use algorithms that require random access. Since random-access iterators encompass all of the characteristics of the other iterators, vectors can use algorithms designed for other iterators as well.

The following code creates and uses an iterator with a vector:

  vector<int> the_vector;
  vector<int>::iterator the_iterator;
  for( int i=0; i < 10; i++ )
    the_vector.push_back(i);
  int total = 0;
  the_iterator = the_vector.begin();
  while( the_iterator != the_vector.end() ) {
    total += *the_iterator;
    the_iterator++;
  }
  cout << "Total=" << total << endl;