C + + Stl:vector and List

STL Description:

The C + + standard module library is a set of template classes that provide a common programming data structure and function, such as a double join table (list), paired array (map), extensible array (vector), large string of storage operations (rope), and so on. The STL library can be obtained from the http://www.sgi.com/tech/stl/.

STL can be divided into the following categories: Container class: Sequential container:Vector: A dynamic array variable, struct, or object. You can insert data at the end to support quick random access.deque: Supports inserting elements, two-terminal queues, before and after arrays.List: A variable, structure, or object that is based on a linked list. You can insert and delete elements anywhere. Support for quick inserts, deletes. Associated containers:Set(No duplicate elements are allowed in set),Multiset(can have duplicate elements): Balanced binary tree structure ordered data collection, can quickly search.Map(Unique keys),Multimap(Allow repeat keys): A balanced binary tree structure that associates key-value pairs. Container adapters:StackLIFO StackQueueFIFO queuepriority_queueReturns the highest-priority element, the priority queue string:string: string and its operationRope: String storage and manipulationBitset: An intuitive storage bit and an action bit. Generic algorithm:Iterator iterator: Represents the position in the container, and an iterator is defined as a container class type.algorithm Algorithm: A class that provides lookups, counts, and searches for elements in a container.Smart pointer auto_ptr: A class that associates memory pointers to avoid memory leaks.STL Vector: Initialize:       Vector<int> Ivec;      Vector<int > Vec2 (IVEC);       Vector c (iter.begin,iter.end);        Vecotr<int > C (5,0); Vector<int> C (5);
Example 1:Use vector to store STL strings and access the elements in the vector with three method classes:

#include <iostream> #include <vector> #include <string> using namespace std;

   Main () {vector<string> SS;
   Ss.push_back ("The number is 10");
   Ss.push_back ("The number is 20");

   Ss.push_back ("The number is 30");

   cout << "Loop by index:" << Endl;
   int II;
   For (Ii=0 II < ss.size (); ii++)//First method access {cout << ss[ii] << Endl;

   } cout << Endl << "Constant iterator:" << Endl;
   Vector<string>::const_iterator CII;
   For (Cii=ss.begin (); Cii!=ss.end (); cii++)//The second method {cout << *cii << Endl;

   } cout << Endl << "Reverse iterator:" << Endl;
   Vector<string>::reverse_iterator Rii;
   For (Rii=ss.rbegin (); Rii!=ss.rend (); ++rii)//third method {cout << *rii << Endl;

   } cout << Endl << "Sample Output:" << Endl;
   cout << ss.size () << Endl;

   cout << ss[2] << Endl; Swap (SS[0], ss[2]);
cout << ss[2] << Endl;
                
 }

vector to represent two-dimensional, three-dimensional arrays:
A two-dimensional array is the length of the array that two Vector,vector constructors can initialize and sets the initial value. Example 2: vector two-dimensional array

#include <iostream>
#include <vector>

using namespace std;

Main ()
{
   //declaration of large and initialized two-dimensional arrays
   vector< vector<int> > Vi2matrix (3, vector<int> (2,0));    

   Vi2matrix[0][0] = 0;
   VI2MATRIX[0][1] = 1;
   Vi2matrix[1][0] = ten;
   VI2MATRIX[1][1] = one;
   Vi2matrix[2][0] =;
   VI2MATRIX[2][1] =;

   cout << "Loop by index:" << Endl;

   int II, JJ;
   For (Ii=0 II < 3; ii++)
   {for
      (jj=0; J.J. < 2; jj++)
      {
         cout << VI2MATRIX[II][JJ] << End l;
      }}}

                

Example 3 :Vector three-dimensional array

#include <iostream>
#include <vector>

using namespace std;

Main ()
{
                               //Vector length of 3 initialized to 0
   vector<int> Vi1matrix (3,0);

                               Vector length of 4 initialized to hold another 

                               /vector vi1matrix which has been initialized to 0
   vector< V Ector<int> > Vi2matrix (4, Vi1matrix);

                               Vector of length 5 containing two dimensional vectors
   vector< vector< vector<int> > > Vi3matrix ( 5, Vi2matrix);

   ...

or, in a statement, define:

#include <iostream>
#include <vector>

using namespace std;

Main ()
{
   vector< vector< vector<int> > > Vi3matrix (2, vector< vector<int> > (3, Vector<int> (4,0)));

   for (int kk=0; kk<4; kk++)
   {for
      (int jj=0; jj<3; jj++) {for
         (int ii=0; ii<2; ii++)
            { cout << Vi3matrix[ii][jj][kk] << Endl}}}

using iterators: Example 4:Using iterators for two-dimensional vectors

#include <iostream>
#include <vector>

using namespace std;

Main ()
{
   vector< vector<int> > Vi2matrix;    Declare two-dimensional array
   vector<int> A, B;
   vector< vector<int> >::iterator Iter_ii;
   Vector<int>::iterator   iter_jj;

   A.push_back (ten);
   A.push_back (a);
   A.push_back (a);
   B.push_back (m);
   B.push_back ();
   B.push_back ();

   Vi2matrix.push_back (A);
   Vi2matrix.push_back (B);

   cout << Endl << "Using iterator:" << Endl;

   For (Iter_ii=vi2matrix.begin (), Iter_ii!=vi2matrix.end (); iter_ii++)
   {for
      (iter_jj= (*iter_ii). Begin (); Iter_jj!= (*iter_ii). end (); iter_jj++)
      {
         cout << *iter_jj << endl;
      }
   }
}
                

Constructor/declaration:

Method/Action	Description
Vector<t> v;	Declares a vector variable V with a data type of "T".
Vector<t> V (size_type N);	Declares a vector variable with a size of n, containing the data type T
Vector<t> V (size_type n,const t& T);	Declares a vector variable with a size of n, containing a data type of T, and an element with a value of t Declaration:vector (size_type N, const t& T)
Vector<t> V (begin_iterator,end_iterator);	Copy a vector from the start position of the iterator to the end position Declaration:template Vector (Inputiterator, inputiterator)

Size Method/action:

td>returns bool (true/false). True if empty. Declaration:bool Empty () const

method/operator	Description
empty ()
size ()	number of elements of vector. Declaration:size_type size () const
resize (n, t=t ())	Adjust by adding or Deleti ng elements of vector so it's size is "n". Declaration:void Resize (n, t = t ())
Capacity ()	Max number of elements of vector before reallocation. Declaration:size_type capacity () const
Reserve (size_t N)	Max Number of element s of vector set to "n" before reallocation. Declaration:void Reserve (size_t)
max_size ()	max number of elements of vector possible. Declaration:size_type max_size () const

Other methods and actions:

Method/operator	Description
Erase () Clear ()	Erase all elements of vector. Declaration:void Clear ()
Erase (iterator) Erase (Begin_iterator,end_iterator)	Erase element of vector. Returns iterator to next element. Erase element range of vector. Returns iterator to next element. Declarations:iterator Erase (iterator pos) iterator erase (iterator-I, iterator, last)
= Example:x=y ()	Assign/copy entire contents of one vector into another. declaration:vector& operator= (const vector&)
<	Comparison of one vector to another. Declaration:bool operator< (const vector&, const vector&)
==	Returns BOOL. True if every element is equal. Declaration:bool operator== (const vector&, const vector&)
at (index) V[index]	Element of Vector. Left and right value assignment:v.at (i) =e; and e=v.at (i); Declaration:reference operator[] (size_type N)
Front () V[0]	The vector of the A-element. (Left and right value assignment.) Declaration:reference Front ()
Back ()	last element of vector. (Left and right value assignment.) Declaration:reference back ()
Push_back (const t& value)	ADD element to end of vector. Declaration:void push_back (const t&)
Pop_back ()	Remove element from end of vector. Declaration:void Pop_back ()
Assign (Size_type n,const t& T)	Assign the elements a value "T".
Assign (Begin_iterator,end_iterator)	Replace data in range defined by iterators. Declaration:
Insert (iterator, const t& T)	Insert at Element "iterator", element of value "T". Declaration:iterator Insert (iterator pos, const t& x)
Insert (iterator Pos, size_type N, const t& x)	Starting before Element "POS", insert a-n elements of value "X". Declaration:void Insert (iterator pos, size_type N, const t& x)
Insert (iterator POS, begin_iterator,end_iterator)	Starting before Element "POS", insert range begin_iterator to End_iterator. Declaration:void Insert (iterator Pos, Inputiterator F, inputiterator L)
Swap (vector& v2)	Swap contents of two vectors. Declaration:void Swap (vector&)

Iterator Methods/Actions

Method/operator	Description
Begin ()	Return iterator to a vector. Declaration:const_iterator begin () const
End ()	Return iterator to end of vectors (not last element of vector but past last element) Declaration:const_iterator End () const
Rbegin ()	Return iterator to a vector (reverse order). Declaration:const_reverse_iterator Rbegin () const
Rend ()	Return iterator to end of vectors (not last element but past last element) (reverse order). Declaration:const_reverse_iterator rend () const
++	Increment iterator.
--	Decrement iterator.

STL list:

Two examples: the first for the data type int second for class instance Example 1:

Standard Template Library Example

#include <iostream>
#include <list>
using namespace std;< C4/>main ()
{
   list<int> L;
   L.push_back (0);              Insert a new element at the end
   L.push_front (0);             Insert a new element
   at the beginning L.insert (++l.begin (), 2);     Insert "2" before position of the argument
                                //(place before second argument)
   L.push_back (5);
   L.push_back (6);

   List<int>::iterator i;

   For (I=l.begin (); I!= l.end (); ++i) cout << *i << "";
   cout << Endl;
   return 0;
}

Example 2: If you use a custom type, you need to include the following: A. Copy constructors
B. Assignment operator (=) overload C. Less than operator overload < d. equals operator = = Overload

#include <iostream> #include <list> using namespace std;

The STL list needs to be overloaded operators =, = =.

   Class AAA {friend Ostream &operator<< (ostream, const AAA &);
      Public:int x;
      int y;

      float Z;
      AAA ();
      AAA (const AAA &);
      ~aaa () {};
      AAA &operator= (const AAA &AMP;RHS);
      int operator== (const AAA &AMP;RHS) const;
int operator< (const AAA &AMP;RHS) const;

};
   AAA::AAA ()//constructor {x = 0;
   y = 0;
z = 0;
   } aaa::aaa (const AAA &in)//copy constructor, pass value {x = copyin.x;
   y = copyin.y;
z = copyin.z;  } ostream &operator<< (ostream &output, const AAA &aaa) {output << aaa.x << ' <<
   Aaa.y << ' << aaa.z << Endl;
return output;
   } aaa& aaa::operator= (const AAA &AMP;RHS) {this->x = rhs.x;
   This->y = Rhs.y;
   This->z = rhs.z;
return *this; int aaa::operator== (const AAA &AMP;RHS) Const {if (this->x!= rhs.x) return 0;
   if (this->y!= rhs.y) return 0;
   if (this->z!= rhs.z) return 0;
return 1; //This function is to allow the STL list to support sort int aaa::operator< (const AAA &AMP;RHS) Const {if (this->x = = Rhs.x && THIS-&G
   T;y = = Rhs.y && this->z < rhs.z) return 1;
   if (this->x = = rhs.x && this->y < RHS.Y) return 1;
   if (This->x < rhs.x) return 1;
return 0;
   Main () {list<aaa> L;

   AAA Ablob;
   ablob.x=7;
   ablob.y=2;
   ablob.z=4.2355;  L.push_back (ABLOB);
   Inserts a new element at the end ablob.x=5;  L.push_back (ABLOB);
   Pass the value, using the default copy constructor//ablob.z=3.2355; 

   L.push_back (ABLOB);
   ablob.x=3;
   ablob.y=7;
   ablob.z=7.2355; 

   L.push_back (ABLOB);

   List<aaa>::iterator i; For (I=l.begin (); I!= l.end (); ++i) cout << (*i). x << "";      

   Print member cout << Endl; For (I=l.begin (); I!= l.end (); ++i) cout << *i << " ";

   Print with overloaded operator cout << Endl;
   cout << "Sorted:" << Endl;
   L.sort (); For (I=l.begin (); I!= l.end (); ++i) cout << *i << "";

   Print with overloaded operator cout << Endl;
return 0;

                
 }

Output results:

7 5 5 3 
7 2 4.2355
 5 2 4.2355
 5 2 3.2355
 3 7 7.2355
 
Sorted:
3 7 7.2355 5 2
 3.2355
 5 2 4.23
 7 2 4.2355

STL vector and list function comparison:

Function	Vector	List
Constructor	Yes	Yes
destructor	Yes	Yes
Empty ()	Yes	Yes
Size ()	Yes	Yes
Resize ()	Yes	Yes
Capacity ()	Yes	No
Reserve ()	Yes	No
Max_size ()	Yes	Yes
Erase ()	Yes	Yes
Clear ()	Yes	Yes
Operator=	Yes	Yes
operator<	Yes	Yes
operator==	Yes	Yes
Operator[]	Yes	No
at ()	Yes	No
Front ()	Yes	Yes
Back ()	Yes	Yes
Push_back ()	Yes	Yes
Pop_back ()	Yes	Yes
Assign ()	Yes	Yes
Insert ()	Yes	Yes
Swap ()	Yes	Yes
Push_front ()	No	Yes
Pop_front ()	No	Yes
Merge ()	No	Yes
Remove ()	No	Yes
Remove_if ()	No	Yes
Reverse ()	No	Yes
Sort ()	No	Yes
Splice ()	No	Yes
Unique ()	No	Yes