std::map::begin, std::map::cbegin

 

C++

Language

Standard library headers

Concepts

Utilities library

Strings library

Containers library

Algorithms library

Iterators library

Numerics library

Input/output library

Localizations library

Regular expressions library (C++11)

Atomic operations library (C++11)

Thread support library (C++11)

Filesystem library (C++17)

Technical Specifications

 

Containers library

array (C++11)

vector

deque

forward_list (C++11)

list

set

multiset

map

multimap

unordered_set (C++11)

unordered_multiset (C++11)

unordered_map (C++11)

unordered_multimap (C++11)

stack

queue

priority_queue

 

std::map

Member functions

map::map

map::~map

map::operator=

map::get_allocator

Element access

map::at

map::operator[]

Iterators

map::beginmap::cbegin (C++11)

map::endmap::cend (C++11)

map::rbeginmap::crbegin (C++11)

map::rendmap::crend (C++11)

Capacity

map::empty

map::size

map::max_size

Modifiers

map::clear

map::insert

map::insert_or_assign (C++17)

map::emplace (C++11)

map::emplace_hint (C++11)

map::try_emplace (C++17)

map::erase

map::swap

Lookup

map::count

map::find

map::equal_range

map::lower_bound

map::upper_bound

Observers

map::key_comp

map::value_comp

 

iterator begin();
const_iterator begin() const;
const_iterator cbegin() const;		(since C++11)

Returns an iterator to the first element of the container.

If the container is empty, the returned iterator will be equal to end().

Parameters

(none)

Return value

Iterator to the first element

Exceptions

(none)	(until C++11)
noexcept specification:   noexcept	(since C++11)

Complexity

Constant

Example

Run this code

#include <iostream>
#include <map>
 
int main() {
  std::map<int, float> a_map;
  a_map[4] = 4.13;
  a_map[9] = 9.24;
  a_map[1] = 1.09;
  for (auto it : a_map) { // calls a_map.begin() and a_map.end()
    std::cout << it.first << ", " << it.second << '\n';
  }
}

Output:

1, 1.09
4, 4.13
9, 9.24

See also

end cend	returns an iterator to the end (public member function)