std::vector<T,Allocator>::front

 

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std::vector

Member types
Member functions
vector::vector vector::~vector vector::operator= vector::assign vector::assign_range (C++23)   vector::get_allocator Element access vector::operator[] vector::at vector::data vector::front vector::back 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 (DR*) Modifiers vector::clear vector::erase vector::insert vector::insert_range (C++23) vector::append_range (C++23) vector::emplace (C++11) vector::emplace_back (C++11) vector::push_back vector::pop_back vector::resize vector::swap
Non-member functions
operator==operator<=> (C++20) swap(std::vector) erase(std::vector)erase_if(std::vector) (C++20)(C++20)	operator!=operator<operator>operator<=operator>= (until C++20)(until C++20)(until C++20)(until C++20)(until C++20)
Deduction guides(C++17)

 

reference front();	(1)	(constexpr since C++20)
const_reference front() const;	(2)	(constexpr since C++20)

Returns a reference to the first element in the container.

Calling front on an empty container causes undefined behavior.

Parameters

(none)

Return value

Reference to the first element.

Complexity

Constant.

Notes

For a container c, the expression c.front() is equivalent to *c.begin().

Example

The following code uses front to display the first element of a std::vector<char>:

Run this code

#include <cassert>
#include <vector>
 
int main()
{
    std::vector<char> letters{'a', 'b', 'c', 'd'};
    assert(letters.front() == 'a');
}

See also

back	access the last element (public member function)
rendcrend (C++11)	returns a reverse iterator to the end (public member function)
begincbegin (C++11)	returns an iterator to the beginning (public member function)
data	direct access to the underlying contiguous storage (public member function)