std::forward_list::splice_after

void splice_after(const_iterator pos, forward_list& other);	(1)	(since C++11)
void splice_after(const_iterator pos, forward_list&& other);	(1)	(since C++11)
void splice_after(const_iterator pos, forward_list& other, const_iterator it);	(2)	(since C++11)
void splice_after(const_iterator pos, forward_list&& other, const_iterator it);	(2)	(since C++11)
void splice_after(const_iterator pos, forward_list& other,                   const_iterator first, const_iterator last);	(3)	(since C++11)
void splice_after(const_iterator pos, forward_list&& other,                   const_iterator first, const_iterator last);	(3)	(since C++11)

Moves elements from another forward_list to *this.

No elements are copied. pos is a valid iterator in *this or is the before_begin() iterator. The behavior is undefined if get_allocator() != other.get_allocator(). No iterators or references become invalidated, the iterators to moved elements now refer into *this, not into other.

1) Moves all elements from other into *this. The elements are inserted after the element pointed to by pos. The container other becomes empty after the operation. The behavior is undefined if this == &other

2) Moves the element pointed to by it from other into *this. The element is inserted after the element pointed to by pos.

3) Moves the elements in the range (first, last) from other into *this. The elements are inserted after the element pointed to by pos. The element pointed-to by first is not moved. The behavior is undefined if pos is an iterator in the range (first,last).

Parameters

pos	-	element after which the content will be inserted
other	-	another container to move the content from
it	-	the element to move from other to *this
first, last	-	the range of elements to move from other to *this

Return value

(none)

Complexity

1) Linear in the size of other

2) Constant

3) Linear in std::distance(first, last)

Example

Demonstrates the meaning of open interval (first, last) in the third form of splice_after(): the first element of l1 is not moved.

#include <iostream>
#include <forward_list>
int main()
{
    std::forward_list<int> l1 = {1,2,3,4,5};
    std::forward_list<int> l2 = {10,11,12};
 
    l2.splice_after(l2.cbegin(), l1, l1.cbegin(), l1.cend());
    // not equivalent to l2.splice_after(l2.cbegin(), l1);
 
    for(int n : l1)
        std::cout << n << ' ';
    std::cout << '\n';
 
    for(int n : l2)
        std::cout << n << ' ';
    std::cout << '\n';
}

Output:

1
10 2 3 4 5 11 12

See also

merge	merges two sorted lists (public member function)
remove remove_if	removes elements satisfying specific criteria (public member function)