Q157560: STL Sample for the merge Function
Article: Q157560
Product(s): Microsoft C Compiler
Version(s): winnt:
Operating System(s):
Keyword(s): _IK
Last Modified: 05-MAY-2001
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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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