DOCUMENT:Q157560  05-MAY-2001  [visualc]
TITLE   :STL Sample for the merge Function
PRODUCT :Microsoft C Compiler
PROD/VER:winnt:
OPER/SYS:
KEYWORDS:_IK

======================================================================
-------------------------------------------------------------------------------
The information in this article applies to:

 - The Standard C++ Library, included with:
    - *EDITOR Please do not choose this product*Microsoft Visual C++ 32-bit Edition* use 241, 265, 225, version 4.2 
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SUMMARY
=======

The sample code below illustrates how to use the merge STL function in Visual
C++.

MORE INFORMATION
================

Required Header
---------------

      <algorithm>

Prototype
---------

      template<class InputIterator1,
               class InputIterator2,
               class OutputIterator> inline
      OutputIterator merge( InputIterator1 first1,
                            InputIterator1 last1,
                            InputIterator2 first2,
                            InputIterator2 last2
                            OutputIterator result )

NOTE: The class/parameter names in the prototype do not match the original
version in the header file. They have been modified to improve readability.

Description
-----------

The merge algorithm merges two sorted sequences: [first1..last1) and
[first2..last2) into a single sorted sequence starting at result.

This version assumes that the ranges [first1..last1) and [first2..last2) are
sorted using operator<. If both ranges contain equal values, the value from
the first range will be stored first.

The result of merging overlapping ranges is undefined.

Sample Code
-----------

   ////////////////////////////////////////////////////////////////////// 
   // 
   // Compile options needed: /GX
   // 
   // merge.cpp : Illustrates how to use the merge
   //                     function.
   // 
   // Functions:
   // 
   //    merge : Merge two sorted sequences
   //            into a single sorted list.
   // 
   // Written by Kalindi Sanghrajka
   // of Microsoft Product Support Services,
   // Software Core Developer Support.
   // Copyright (c) 1996 Microsoft Corporation. All rights reserved.
   ////////////////////////////////////////////////////////////////////// 

   // disable warning C4786: symbol greater than 255 character,
   // okay to ignore
   #pragma warning(disable: 4786)

   #include <iostream>
   #include <algorithm>
   #include <vector>
   #include <list>
   #include <deque>
   using namespace std;

   void main()
   {
       const int MAX_ELEMENTS = 8 ;

       // Define a template class vector of int
       typedef vector<int, allocator<int> > IntVector ;

       //Define an iterator for template class vector of ints
       typedef IntVector::iterator IntVectorIt ;

       IntVector NumbersVector(MAX_ELEMENTS) ;

       IntVectorIt startv, endv, itv ;

       // Define a template class list of int
       typedef list<int, allocator<int> > IntList ;

       //Define an iterator for template class list of ints
       typedef IntList::iterator IntListIt ;

       IntList NumbersList ;

       IntListIt first, last, itl ;

       // Define a template class deque of int
       typedef deque<int, allocator<int> > IntDeque ;

       //Define an iterator for template class deque of ints
       typedef IntDeque::iterator IntDequeIt ;

       IntDeque NumbersDeque(2 * MAX_ELEMENTS) ;

       IntDequeIt itd ;

       // Initialize vector NumbersVector
       NumbersVector[0] = 4 ;
       NumbersVector[1] = 10;
       NumbersVector[2] = 70 ;
       NumbersVector[3] = 10 ;
       NumbersVector[4] = 30 ;
       NumbersVector[5] = 69 ;
       NumbersVector[6] = 96 ;
       NumbersVector[7] = 100;

       startv = NumbersVector.begin() ;   // location of first
                                          // element of NumbersVector

       endv = NumbersVector.end() ;  // one past the location
                                     // last element of NumbersVector

       // sort NumbersVector, merge requires the sequences
       // to be sorted
       sort(startv, endv) ;

       // print content of NumbersVector
       cout << "NumbersVector { " ;
       for(itv = startv; itv != endv; itv++)
           cout << *itv << " " ;
       cout << " }\n" << endl ;

       // Initialize vector NumbersList
       for(int i = 0; i < MAX_ELEMENTS; i++)
           NumbersList.push_back(i) ;

       first = NumbersList.begin() ;   // location of first
                                        // element of NumbersList

       last = NumbersList.end() ;  // one past the location
                                   // last element of NumbersList

       // print content of NumbersList
       cout << "NumbersList { " ;
       for(itl = first; itl != last; itl++)
           cout << *itl << " " ;
       cout << " }\n" << endl ;

       // merge the elements of NumbersVector
       // and NumbersList and place the
       // results in NumbersDeque
       merge(startv, endv, first, last, NumbersDeque.begin()) ;

       cout << "After calling merge\n" << endl ;

       // print content of NumbersDeque
       cout << "NumbersDeque { " ;
       for(itd = NumbersDeque.begin();
           itd != NumbersDeque.end(); itd++)
           cout << *itd << " " ;
       cout << " }\n" << endl ;
   }

   Program Output is:

   NumbersVector { 4 10 10 30 69 70 96 100  }

   NumbersList { 0 1 2 3 4 5 6 7  }

   After calling merge

   NumbersDeque { 0 1 2 3 4 4 5 6 7 10 10 30 69 70 96 100  }

REFERENCES
==========

Visual C++ Books On Line: Visual C++ Books:C/C++:Standard C++ Library Reference.

Additional query words: STL merge

======================================================================
Keywords          : _IK 
Technology        : kbVCsearch kbAudDeveloper kbVCLibrary
Version           : winnt:
Issue type        : kbhowto

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