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std::forward_list<T,Allocator>::splice_after

From cppreference.com
 
 
 
 
void splice_after( const_iterator pos, forward_list& other );
(1) (since C++11)
void splice_after( const_iterator pos, forward_list&& other );
(2) (since C++11)
void splice_after( const_iterator pos, forward_list& other,
                   const_iterator it );
(3) (since C++11)
void splice_after( const_iterator pos, forward_list&& other,
                   const_iterator it );
(4) (since C++11)
void splice_after( const_iterator pos, forward_list& other,
                   const_iterator first, const_iterator last );
(5) (since C++11)
void splice_after( const_iterator pos, forward_list&& other,
                   const_iterator first, const_iterator last );
(6) (since C++11)

Moves elements from another forward_list to *this. The elements are inserted after the element pointed to by pos.

No elements are copied. No iterators or references become invalidated. The iterators to the moved elements now refer into *this, not into other.

1,2) Moves all elements from other into *this. The container other becomes empty after the operation.
3,4) Moves the element pointed to by the iterator following it from other into *this. Has no effect if pos == it or if pos == ++it.
5,6) Moves the elements in the range (firstlast) from other into *this. The element pointed-to by first is not moved.

The behavior is undefined if

  • get_allocator() != other.get_allocator(),
  • pos is neither before_begin() nor a dereferenceable iterator in [begin()end()),
  • for overloads (1,2), *this and other refer to the same object,
  • for overloads (3,4), the iterator following it is not a dereferenceable iterator into other, or
  • for overloads (5,6),
  • (firstlast) is not a valid range in other,
  • some iterators in (firstlast) are not dereferenceable, or
  • pos is in (firstlast).

Contents

[edit] Parameters

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

[edit] Return value

(none)

[edit] Exceptions

Throws nothing.

[edit] Complexity

1,2) Linear in the size of other.
3,4) Constant.
5,6) Linear in std::distance(first, last).

[edit] Example

#include <cassert>
#include <forward_list>
 
int main()
{
    using F = std::forward_list<int>;
 
    // Demonstrate the meaning of open range (first, last)
    // in overload (5): the first element of l1 is not moved.
    F l1 = {1, 2, 3, 4, 5};
    F l2 = {10, 11, 12};
 
    l2.splice_after(l2.cbegin(), l1, l1.cbegin(), l1.cend());
    // Not equivalent to l2.splice_after(l2.cbegin(), l1);
    // which is equivalent to
    // l2.splice_after(l2.cbegin(), l1, l1.cbefore_begin(), l1.end());
 
    assert((l1 == F{1}));
    assert((l2 == F{10, 2, 3, 4, 5, 11, 12}));
 
    // Overload (1)
    F x = {1, 2, 3, 4, 5};
    F y = {10, 11, 12};
    x.splice_after(x.cbegin(), y);
    assert((x == F{1, 10, 11, 12, 2, 3, 4, 5}));
    assert((y == F{}));
 
    // Overload (3)
    x = {1, 2, 3, 4, 5};
    y = {10, 11, 12};
    x.splice_after(x.cbegin(), y, y.cbegin());
    assert((x == F{1, 11, 2, 3, 4, 5}));
    assert((y == F{10, 12}));
 
    // Overload (5)
    x = {1, 2, 3, 4, 5};
    y = {10, 11, 12};
    x.splice_after(x.cbegin(), y, y.cbegin(), y.cend());
    assert((x == F{1, 11, 12, 2, 3, 4, 5}));
    assert((y == F{10}));
}

[edit] Defect reports

The following behavior-changing defect reports were applied retroactively to previously published C++ standards.

DR Applied to Behavior as published Correct behavior
LWG 2045 C++11 O(1) splicing could not be guaranteed if
get_allocator() != other.get_allocator()
the behavior is
undefined in this case

[edit] See also

merges two sorted lists
(public member function) [edit]
removes elements satisfying specific criteria
(public member function) [edit]
returns an iterator to the element before beginning
(public member function) [edit]