std::vector<T,Allocator>::push_back (3) - Linux Man Pages

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

NAME

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

Synopsis


void push_back( const T& value ); (1)
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.

Parameters


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


(none)

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 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)

Notes


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).

Example


// Run this code


  #include <vector>
  #include <iostream>
  #include <iomanip>


  int main()
  {
      std::vector<std::string> numbers;


      numbers.push_back("abc");
      std::string s = "def";
      numbers.push_back(std::move(s));


      std::cout << "vector holds: ";
      for (auto&& i : numbers) std::cout << std::quoted(i) << ' ';
      std::cout << "\nMoved-from string holds " << std::quoted(s) << '\n';
  }

Output:


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

See also


emplace_back constructs an element in-place at the end
             (public member function)
(C++11)
             removes the last element
pop_back (public member function)