< cpp‎ | container‎ | vector

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

Appends the given element value to the end of the container.

1) The new element is initialized as a copy of value.
2) value is moved into the new element.

If the new size() is greater than capacity() then all iterators and references (including the past-the-end iterator) are invalidated. Otherwise only the past-the-end iterator is invalidated.


value - the value of the element to append
Type requirements
T must meet the requirements of CopyInsertable in order to use overload (1).
T must meet the requirements of MoveInsertable in order to use overload (2).

Return value



Amortized constant.


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 T's move constructor 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)


Some implementations also throw std::length_error when push_back causes a reallocation that would exceed max_size, due to implicitly calling an equivalent of reserve(size()+1).


#include <vector>
#include <iostream>
#include <iomanip>
int main()
    std::vector<std::string> numbers;
    std::string s = "def";
    std::cout << "vector holds: ";
    for (auto&& i : numbers) std::cout << std::quoted(i) << ' ';
    std::cout << "\nMoved-from string holds " << std::quoted(s) << '\n';


vector holds: "abc" "def" 
Moved-from string holds ""

See also

constructs an element in-place at the end
(public member function)
removes the last element
(public member function)