Deque Dual-ended queue container

C + + in the STL is still more useful, especially in the implementation of scientific research algorithms, but also useful, but not how the system has been studied, so recently looked for a book, Ye Zhijun the "C + + STL development Technology Guidance", science, the nature of a book, written relatively shallow [hehe, do not spray ]。 Most of the content below is excerpted from the book.
Deque double-ended queue container (double-ended queue), can be inserted in the tail, head, delete elements, the use of a block of linear structure to store data, two iterators point to the first and the end of the container, the deque block for memory allocation, using a two-level map for management.

Create a Deque object

There are several ways to create the Deque container object.
(1) deque ()
The Deque container created in this way already has an object, except that the tail-to-kinsoku iterator overlaps, and there are no elements in the container.

deque<int> d;

(2) Deque (size_type N)
Creates a Deque object with n elements, each with a default value of the corresponding type.

deque<int> d(10);//10个元素的初始值为0

(3) deque (size_type n,const t& value)
Creates a Deque object with n elements with an initial value of values.

deque<double> d(10,2.5);

(4) deque (const deque&)
Copy constructor.

deque<char> d1(5,’k’);deque<char> d2(d1);

(5) deque (const inputiterator first,const inputiterator last,const a&a=a ())

intarray[]={1,2,3,4,5};deque<int>d(array,array+5);

Deque initialization

Use the Push_back function to press the new element at the tail.

deque<int> d;d.push_back(10);

Traversal access of elements

can be accessed in the form of arrays and iterators.
To access the Deque element using an array method:

#include <iostream>#include <deque>using namespace STD;intMain () { deque<int>D D.push_back (1); D.push_back (2); D.push_back (3); D.push_back (4); for(intI=0; I<d.size (); i++) {cout<<"d["<<i<<"]="<<d[i]<<endl; }return 0;}

To access the Deque element with an iterator:

#include <iostream>#include <deque>using namespace STD;intMain () { deque<int>D D.push_back (1); D.push_back (2); D.push_back (3); D.push_back (4); deque<int>:: Iterator Begin,end; End=d.end ();intI for(Begin=d.begin (), i=0; begin!=end;begin++,i++) {cout<<*begin<<endl; }return 0;}

Insertion of elements

Deque uses two iterators to point to the end of a double-ended queue, Deque has a function push_front () with an efficient head insertion element, and its prototype is:

void push_front(const T&);

The insertion of other locations involves a shift copy of the element, and the Insert function inserts the element x before the POS position,

Iterator insert(iterator pos,const T& x);

Cases:

#include <iostream>#include <deque>using namespace STD;intMain () { deque<int>D D.push_back (1); D.push_back (2);//Head insertionD.push_front (3); for(intI=0; I<d.size (); i++) {cout<<d[i]<<" "; }cout<<endl;//Middle position insertionD.insert (D.begin () +2,4);//Insert 4 before the 3rd element     for(intI=0; I<d.size (); i++)cout<<d[i]<<" ";cout<<endl;return 0;}

Deletion of elements

Delete the first element Pop_front function, delete the tail element pop_back function, delete any position or iteration interval erase function, delete all element clear function.

#include <iostream>#include <deque>using namespace STD;intMain () { deque<int>D D.push_back (1); D.push_back (2); D.push_back (3); D.push_back (4); D.push_back (5); for(intI=0; I<d.size (); i++) {cout<<d[i]<<" "; }cout<<endl;//tail and anywhere delete elementD.erase (D.begin () +2);//Delete element 3rdD.pop_front (); D.pop_back (); for(intI=0; I<d.size (); i++) {cout<<d[i]<<" "; }cout<<endl; D.clear ();//Delete all elements    cout<<d.size () <<endl;return 0;}

Reverse traversal of elements

Reverse iterators reverse_iterator and const_reverse_iterator.

#include <iostream>#include <deque>using namespace STD;intMain () { deque<int>D D.push_back (1); D.push_back (2); D.push_back (3); D.push_back (4); D.push_back (5);//forward traversal     deque<int>:: Iterator Begin,end; End=d.end (); for(Begin=d.begin (); begin!=end;begin++)cout<<*begin<<" ";cout<<endl;//Reverse Traversal     deque<int>:: Reverse_iterator rbegin,rend; Rend=d.rend (); for(Rbegin=d.rbegin (); rbegin!=rend;rbegin++)cout<<*rbegin<<" ";cout<<endl;return 0;}

Exchange of Deque

Swap with swap functions.

#include <iostream>#include <deque>using namespace STD;voidPrint deque<int>&AMP;D) { for(intI=0; I<d.size (); i++)cout<<d[i]<<" ";cout<<endl;}intMain () {//d1     deque<int>D1; D1.push_back (1); D1.push_back (2);cout<<"Before-----------Exchange:"<<endl;cout<<"d1="; Print (D1);//d2     deque<int>D2; D2.push_back (3); D2.push_back (4); D2.push_back (5);cout<<"d2="; Print (D2);cout<<"After-----------Exchange:"<<endl; D1.swap (D2);cout<<"d1="; Print (D1);cout<<"d2="; Print (D2);return 0;}

Other functions

BOOL Empty ()
Size_type size ()
Size_type max_size ()
Reference Front ()
Reference back ()

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Deque Dual-ended queue container