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STL Iterators

Iterators are objects that point to elements in a container. They provide a uniform way to traverse different STL containers (vector, list, set, etc.).

THE POINTER ANALOGY

Iterators behave just like pointers. You can increment them (it++) and dereference them (*it).

vector<int> v = {10, 20, 30};
vector<int>::iterator it = v.begin();

cout << *it;    // 10
it++;           // Points to 20
cout << *it;    // 20

begin()

Returns an iterator pointing to the FIRST element.

end()

Returns an iterator pointing to the position AFTER the last element.

AUTO KEYWORD

Iterators often have complex type names. In modern C++, always use auto to simplify your loops.

for (auto it = v.begin(); it != v.end(); it++) { ... }

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