std::list::operator=

 

C++

Language

Concepts

Utilities library

Strings library

Containers library

Algorithms library

Iterators library

Numerics library

Input/output library

Localizations library

Regular expressions library (C++11)

Atomic operations library (C++11)

Thread support library (C++11)

 

Containers library

array (C++11)

vector

deque

forward_list (C++11)

list

set

multiset

map

multimap

unordered_set (C++11)

unordered_multiset (C++11)

unordered_map (C++11)

unordered_multimap (C++11)

stack

queue

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std::list

Member functions

list::list

list::~list

list::operator=

list::assign

list::get_allocator

Element access

list::front

list::back

Iterators

list::begin list::cbegin (C++11)

list::end list::cend (C++11)

list::rbegin list::crbegin (C++11)

list::rend list::crend (C++11)

Capacity

list::empty

list::size

list::max_size

Modifiers

list::clear

list::insert

list::emplace (C++11)

list::erase

list::push_front

list::emplace_front (C++11)

list::pop_front

list::push_back

list::emplace_back (C++11)

list::pop_back

list::resize

list::swap

Operations

list::merge

list::splice

list::remove list::remove_if

list::reverse

list::unique

list::sort

 

list& operator=( const list& other );	(1)
list& operator=( list&& other );	(2)	(since C++11)

Replaces the contents of the container.

1) Copy assignment operator. Replaces the contents with a copy of the contents of other.

2) Move assignment operator. Replaces the contents with those of other using move semantics (i.e. the data in other is moved from other into this container).

Parameters

other

-

another container to be used as source

Return value

*this

Complexity

1) Linear in the size of the container.

2) Constant.

Example

The following code uses to assign one std::list to another:

#include <list>
#include <iostream>
 
void display_sizes(const std::list<int> &nums1,
                   const std::list<int> &nums2,
                   const std::list<int> &nums3)
{
    std::cout << "nums1: " << nums1.size() 
              << " nums2: " << nums2.size()
              << " nums3: " << nums3.size() << '\n';
}
 
int main()
{
    std::list<int> nums1 {3, 1, 4, 6, 5, 9};
    std::list<int> nums2; 
    std::list<int> nums3;
 
    std::cout << "Initially:\n";
    display_sizes(nums1, nums2, nums3);
 
    // copy assignment copies data from nums1 to nums2
    nums2 = nums1;
 
    std::cout << "After assigment:\n"; 
    display_sizes(nums1, nums2, nums3);
 
    // move assignment moves data from nums1 to nums3,
    // modifying both nums1 and nums3
    nums3 = std::move(nums1);
 
    std::cout << "After move assigment:\n"; 
    display_sizes(nums1, nums2, nums3);
}

Output:

Initially:
nums1: 4 nums2: 0 nums3: 0
After assigment:
nums1: 4 nums2: 4 nums3: 0
After move assigment:
nums1: 0 nums2: 4 nums3: 4

See also

(constructor)	constructs the list (public member function)
assign	assigns values to the container (public member function)