vector Class

The STL vector class is a template class of sequence containers that arrange elements of a given type in a linear arrangement and allow fast random access to any element. They should be the preferred container for a sequence when random-access performance is at a premium.

For a list of all members of this type, see vector Members.

template <
   class Type, 
   class Allocator = allocator<Type> 
class vector


  • Type
    The element data type to be stored in the vector

  • Allocator
    The type that represents the stored allocator object that encapsulates details about the vector's allocation and deallocation of memory. This argument is optional and the default value is allocator*<Type>.*


Vectors allow constant time insertions and deletions at the end of the sequence. Inserting or deleting elements in the middle of a vector requires linear time. The performance of the deque Class container is superior with respect to insertions and deletions at the beginning and end of a sequence. The list Class container is superior with respect to insertions and deletions at any location within a sequence.

Vector reallocation occurs when a member function must increase the sequence contained in the vector object beyond its current storage capacity. Other insertions and erasures may alter various storage addresses within the sequence. In all such cases, iterators or references that point at altered portions of the sequence become invalid. If no reallocation happens, only iterators and references before the insertion/deletion point remain valid.

The vector<bool> Class is a full specialization of the template class vector for elements of type bool with an allocator for the underlying type used by the specialization.

The vector<bool> reference Class is a nested class whose objects are able to provide references to elements (single bits) within a vector<bool> object.


Header: <vector>

Namespace: std

See Also


Thread Safety in the Standard C++ Library

Standard Template Library

Other Resources

vector Members

<vector> Members