The three different sequence containers all have different time and space complexities for their different operations:
C array | vector | deque | list |
|
|---|---|---|---|---|
Insert/erase at start | n/a | linear | constant | constant |
Insert/erase at end | n/a | constant | constant | constant |
Insert/erase in middle | n/a | linear | linear | constant |
Access first element | constant | constant | constant | constant |
Access last element | constant | constant | constant | constant |
Access middle element | constant | constant | constant | linear |
Overhead | none | low | medium | high |
T(); T(const T&); ~T(); T& operator=(const T&);
#include < iostream.h >
#include < vector.h >
void print (vector < double >& vector_)
{
for (int i = 0; i < vector_.size (); i++)
cout << vector_[i] << " ";
cout << endl;
}
int main ()
{
vector < double > v1; // Empty vector of doubles.
v1.push_back (32.1);
v1.push_back (40.5);
vector< double > v2; // Another empty vector of doubles.
v2.push_back (3.56);
cout << "v1 = ";
print (v1);
cout << "v2 = ";
print (v2);
v1.swap (v2); // Swap the vector's contents.
cout << "v1 = ";
print (v1);
cout << "v2 = ";
print (v2);
v2 = v1; // Assign one vector to another.
cout << "v2 = ";
print (v2);
return 0;
}
output:
v1 = 32.1 40.5 v2 = 3.56 v1 = 3.56 v2 = 32.1 40.5 v2 = 3.56
operator[] is a bit slower.
T(); T(const T&); ~T(); T& operator=(const T&);
#include < iostream.h >
#include < deque.h >
int main ()
{
deque< int > d;
d.push_back (4); // Add after end.
d.push_back (9);
d.push_back (16);
d.push_front (1); // Insert at beginning.
for (int i = 0; i < d.size (); i++)
cout << "d[" << i << "] = " << d[i] << endl;
cout << endl;
d.pop_front (); // Erase first element.
d[2] = 25; // Replace last element.
for (i = 0; i < d.size (); i++)
cout << "d[" << i << "] = " << d[i] << endl;
return 0;
}
output:
d[0] = 1 d[1] = 4 d[2] = 9 d[3] = 16 d[0] = 4 d[1] = 9 d[2] = 25
operator[].
T(); T(const T&); ~T(); T& operator=(const T&); T* operator&();
int operator < (const T&, const T&); int operator==(const T&, const T&);
#include < iostream.h >
#include < list.h >
int array1 [] = { 9, 16, 36 };
int array2 [] = { 1, 4 };
int main ()
{
list< int > l1 (array1, array1 + 3);
list< int > l2 (array2, array2 + 2);
list< int >::iterator i1 = l1.begin ();
l1.splice (i1, l2);
list< int >::iterator i2 = l1.begin ();
while (i2 != l1.end ())
cout << *i2++ << endl;
return 0;
}
output:
1 4 9 16 36
Container adaptors take sequence containers as their type arguments, for example:
stack < vector < int > > a;
- bool empty();
- size_type size();
- value_type& top();
- const value_type& top();
- void push(const value_type&);
- void pop();
- bool empty();
- size_type size();
- value_type& front();
- const value_type& front();
- value_type& back();
- const value_type& back();
- void push(const value_type&);
- void pop();
operator[] is required.)
operator[].
- bool empty();
- size_type size();
- value_type& top();
- const value_type& top();
- void push(const value_type&);
- void pop();
insert(const &T) returns a pair < rep_type::iterator, bool >
to indicate success or failure of a set/map insertion.
insert(const &T) returns a pair < rep_type::iterator, bool >
to indicate success or failure of a set/map insertion.
operator[] can be used like a non-scalar array index.
operator[].