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

 

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std::vector

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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
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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)
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void push_back(const T& value );	(1)	(constexpr since C++20)
void push_back( T&& value );	(2)	(since C++11) (constexpr since C++20)

Appends a copy of value to the end of the container.

If after the operation the new size() is greater than old capacity() a reallocation takes place, in which case all iterators (including the end() iterator) and all references to the elements are invalidated. Otherwise only the end() iterator is invalidated.

Parameters

value	-	the value of the element to append
Type requirements
- If the following condition is satisfied, the behavior is undefined: 1)T is not CopyInsertable into vector. 2)T is not MoveInsertable into vector. (since C++11)

Complexity

Amortized constant.

Exceptions

If an exception is thrown (which can be due to Allocator::allocate() or element copy/move constructor/assignment), this function has no effect (strong exception guarantee).

If the move constructor of T is not noexcept and T is not CopyInsertable into *this, vector will use the throwing move constructor. If it throws, the guarantee is waived and the effects are unspecified.

(since C++11)

Notes

Some implementations throw std::length_error when push_back causes a reallocation that exceeds max_size (due to an implicit call to an equivalent of reserve(size() + 1)).

Example

Run this code

#include <iomanip>#include <iostream>#include <string>#include <vector>   int main(){std::vector<std::string> letters;   letters.push_back("abc");std::string s{"def"}; letters.push_back(std::move(s));   std::cout<<"std::vector letters holds: ";for(auto&& e : letters)std::cout<<std::quoted(e)<<' ';   std::cout<<"\nMoved-from string s holds: "<<std::quoted(s)<<'\n';}

Possible output:

std::vector letters holds: "abc" "def" Moved-from string s holds: ""

See also

emplace_back (C++11)	constructs an element in-place at the end (public member function)
pop_back	removes the last element (public member function)
back_inserter	creates a std::back_insert_iterator of type inferred from the argument (function template)