a.insert(p, i, j) | [i,j) is a valid range. | a.size() plus the distance from i to j does not exceed a.max_size(). Inserts a copy of the range [i,j) before p. [1] [2] [3] | a.size() is incremented by the distance from i to j. The relative order of elements already in the sequence is unchanged. |
| Erase | a.erase(p) | p is a dereferenceable iterator in a. | Destroys the element pointed to by p and removes it from a. [3] | a.size() is decremented by 1. The relative order of the other elements in the sequence is unchanged. The return value is an iterator to the element immediately following the one that was erased. |
| Range erase | a.erase(p,q) | [p,q) is a valid range in a. | Destroys the elements in the range [p,q) and removes them from a. [3] | a.size() is decremented by the distance from i to j. The relative order of the other elements in the sequence is unchanged. The return value is an iterator to the element immediately following the ones that were erased. |
| Clear | a.clear() | | Equivalent to a.erase(a.begin(), a.end()) | |
| Resize | a.resize(n, t) | n <= a.max_size() | Modifies the container so that it has exactly n elements, inserting elements at the end or erasing elements from the end if necessary. If any elements are inserted, they are copies of t. If n > a.size() , this expression is equivalent to a.insert(a.end(), n – size(), t). If n < a.size() , it is equivalent to a.erase(a.begin() + n, a.end()). | a.size() == n |
| Resize | a.resize(n) | n <= a.max_size() | Equivalent to a.resize(n, T()). | a.size() == n |
Complexity guarantees The fill constructor, default fill constructor, and range constructor are linear.
Front is amortized constant time.
Fill insert, range insert, and range erase are linear.
The complexities of single-element insert and erase are sequence dependent.
Models • vector [5]
• deque
• list
• slist
Notes [1] At present (early 1998), not all compilers support 'member templates'. If your compiler supports member templates then i and j may be of any type that conforms to the Input Iterator requirements. If your compiler does not yet support member templates, however, then i and j must be of type const T* or of type X::const_iterator.
[2] Note that p equal to a.begin() means to insert something at the beginning of a (that is, before any elements already in a ), and p equal to a.end() means to append something to the end of a.
[3] Warning: there is no guarantee that a valid iterator ona is still valid after an insertion or an erasure. In some cases iterators do remain valid, and in other cases they do not. The details are different for each sequence class.
[4] a.insert(p, n, t) is guaranteed to be no slower then calling a.insert(p, t)n times. In some cases it is significantly faster.
[5] Vector is usually preferable to deque and list. Deque is useful in the case of frequent insertions at both the beginning and end of the sequence, and list and slist are useful in the case of frequent insertions in the middle of the sequence. In almost all other situations, vector is more efficient.
See also Container, Forward Container, Associative Container, Front Insertion Sequence, Back Insertion Sequence, vector, deque, list, slist
Category: containers
Component type: concept
Description A Front Insertion Sequence is a Sequence where it is possible to insert an element at the beginning, or to
