std::set::operator=

 

C++

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Regular expressions library (C++11)

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Containers library

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std::set

Member functions

set::set

set::~set

set::operator=

set::get_allocator

Iterators

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

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

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

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

Capacity

set::empty

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Modifiers

set::clear

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Lookup

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Observers

set::key_comp

set::value_comp

 

set& operator=( const set& other );	(1)
set& operator=( set&& other );	(2)	(since C++11)
set& operator=( std::initializer_list<value_type> ilist );	(3)	(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). other is in a valid but unspecified state afterwards.

3) Replaces the contents with those identified by initializer list ilist.

Parameters

other	-	another container to use as data source
ilist	-	initializer list to use as data source

Return value

*this

Complexity

1) Linear in the size of the other.

2) Constant.

3) Linear in the size of ilist.

Example

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

run this code

#include <set>
#include <iostream>
 
void display_sizes(const std::set<int> &nums1,
                   const std::set<int> &nums2,
                   const std::set<int> &nums3)
{
    std::cout << "nums1: " << nums1.size() 
              << " nums2: " << nums2.size()
              << " nums3: " << nums3.size() << '\n';
}
 
int main()
{
    std::set<int> nums1 {3, 1, 4, 6, 5, 9};
    std::set<int> nums2; 
    std::set<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: 6 nums2: 0 nums3: 0
After assigment:
nums1: 6 nums2: 6 nums3: 0
After move assigment:
nums1: 0 nums2: 6 nums3: 6

See also

(constructor)	constructs the set (public member function)