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

 

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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)

 

T* data();	(1)	(noexcept since C++11) (constexpr since C++20)
const T* data()const;	(2)	(noexcept since C++11) (constexpr since C++20)

Returns a pointer to the underlying array serving as element storage. The pointer is such that range [data(), data()+ size()) is always a valid range, even if the container is empty (data() is not dereferenceable in that case).

Parameters

(none)

Return value

Pointer to the underlying element storage. For non-empty containers, the returned pointer compares equal to the address of the first element.

Complexity

Constant.

Notes

If size() is ​0​, data() may or may not return a null pointer.

Example

Run this code

#include <cstddef>#include <iostream>#include <span>#include <vector>   void pointer_func(constint* p, std::size_t size){std::cout<<"data = ";for(std::size_t i =0; i < size;++i)std::cout<< p[i]<<' ';std::cout<<'\n';}   void span_func(std::span<constint> data)// since C++20{std::cout<<"data = ";for(constint e : data)std::cout<< e <<' ';std::cout<<'\n';}   int main(){std::vector<int> container{1, 2, 3, 4};   // Prefer container.data() over &container[0] pointer_func(container.data(), container.size());   // std::span is a safer alternative to separated pointer/size. span_func({container.data(), container.size()});}

Output:

data = 1 2 3 4 data = 1 2 3 4

Defect reports

The following behavior-changing defect reports were applied retroactively to previously published C++ standards.

DR	Applied to	Behavior as published	Correct behavior
LWG 464	C++98	vector did not have this member function	added
LWG 1312	C++98	the return type were pointer and const_pointer	changed to T* and const T* respectively

See also

front	access the first element (public member function)
back	access the last element (public member function)
size	returns the number of elements (public member function)
operator[]	access specified element (public member function)
span (C++20)	a non-owning view over a contiguous sequence of objects (class template)
data (C++17)	obtains the pointer to the underlying array (function template)