public member function
<set>

std::set::begin

      iterator begin();
const_iterator begin() const;

      iterator begin() noexcept;
const_iterator begin() const noexcept;
Return iterator to beginning
Returns an iterator referring to the first element in the set container.

Because set containers keep their elements ordered at all times, begin points to the element that goes first following the container's sorting criterion.

If the container is empty, the returned iterator value shall not be dereferenced.

Parameters

none

Return Value

An iterator to the first element in the container.

If the set object is const-qualified, the function returns a const_iterator. Otherwise, it returns an iterator.

Member types iterator and const_iterator are bidirectional iterator types pointing to elements.

Example

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// set::begin/end
#include <iostream>
#include <set>

int main ()
{
  int myints[] = {75,23,65,42,13};
  std::set<int> myset (myints,myints+5);

  std::cout << "myset contains:";
  for (std::set<int>::iterator it=myset.begin(); it!=myset.end(); ++it)
    std::cout << ' ' << *it;

  std::cout << '\n';

  return 0;
}


Output:
myset contains: 13 23 42 65 75

Complexity

Constant.

Iterator validity

No changes.

Data races

The container is accessed (neither the const nor the non-const versions modify the container).
Concurrently accessing the elements of a set is safe.

Exception safety

No-throw guarantee: this member function never throws exceptions.
The copy construction or assignment of the returned iterator is also guaranteed to never throw.

See also

set::end
Return iterator to end (public member function )
set::rbegin
Return reverse iterator to reverse beginning (public member function )
set::rend
Return reverse iterator to reverse end (public member function )

C++