std::vector::begin, std::vector::cbegin

C++

Language

Headers

Freestanding and hosted implementations

Named requirements

Language support library

Concepts library (C++20)

Diagnostics library

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

span (C++20)

std::vector

Member functions

vector::vector

vector::~vector

vector::operator=

vector::assign

vector::get_allocator

Element access

vector::at

vector::operator[]

vector::front

vector::back

vector::data (C++11)

Iterators

vector::beginvector::cbegin (C++11)

vector::endvector::cend (C++11)

vector::rbeginvector::crbegin (C++11)

vector::rendvector::crend (C++11)

Capacity

vector::empty

vector::size

vector::max_size

vector::reserve

vector::capacity

vector::shrink_to_fit (C++11)

Modifiers

vector::clear

vector::insert

vector::emplace (C++11)

vector::erase

vector::push_back

vector::emplace_back (C++11)

vector::pop_back

vector::resize

vector::swap

Deduction guides(C++17)

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

Complexity

Constant

Example

Run this code

#include <iostream>
#include <vector>
#include <string>

int main()
{
	std::vector<int> ints {1, 2, 4, 8, 16};
	std::vector<std::string> fruits {"orange", "apple", "raspberry"};
	std::vector<char> empty;

	// Sums all integers in the vector ints (if any), printing only the result.
	int sum = 0;
	for (auto it = ints.cbegin(); it != ints.cend(); it++)
		sum += *it;
	std::cout << "Sum of ints: " << sum << "\n";

	// Prints the first fruit in the vector fruits, without checking if there is one.
	std::cout << "First fruit: " << *fruits.begin() << "\n";

	if (empty.begin() == empty.end())
		std::cout << "vector 'empty' is indeed empty.\n";
}

Output:

Sum of ints: 31
First fruit: orange
vector 'empty' is indeed empty.

See also

end cend

returns an iterator to the end (public member function)