Help and Support
 

powered byLive Search

STL Sample for Predicate Version of next_permutation Function

Retired KB ArticleThis article was written about products for which Microsoft no longer offers support. Therefore, this article is offered "as is" and will no longer be updated.
Article ID:157869
Last Review:December 8, 2003
Revision:2.0
This article was previously published under Q157869
On This Page

SUMMARY

The sample code below illustrates how to use the predicate version of the next_permutation STL function in Visual C++.

Back to the top

MORE INFORMATION

Required Header

   <algorithm>
				

Back to the top

Prototype

   template<class BidirectionalIterator, class Compare> inline
   bool next_permutation(BidirectionalIterator first,
                         BidirectionalIterator last,
                         Compare compare)
				
NOTE: The class/parameter names in the prototype do not match the version in the header file. Some have been modified to improve readability.

Back to the top

Description

The next_permutation algorithm changes the order of the elements in the range [first, last) to the next lexicographic permutation and returns true. If there is no next_permutation, it arranges the sequence to be the first permutation and returns false.

NOTE: The next_permutation algorithm assumes that the sequence is sorted in ascending order using the compare function.

The non-predicate version uses the compare function to order the permutations.

Back to the top

Sample Code

////////////////////////////////////////////////////////////////////// 
// 
// Compile options needed: /GX
// 
// next_permutation.cpp : Illustrates how to use the predicate version
//                        of the next_permutation function.
// 
// Functions:
// 
//    next_permutation : Change the order of the sequence to the
//                       next lexicograhic permutation.
// 
// 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 <vector>
#include <string>
#include <algorithm>
#include <functional>
using namespace std;

void main()
{
    const int VECTOR_SIZE = 3 ;

    // Define a template class vector of strings
    typedef vector<string, allocator<string> > StrVector ;

    //Define an iterator for template class vector of strings
    typedef StrVector::iterator StrVectorIt ;

    //Define an ostream iterator for strings
    typedef ostream_iterator<string,char,char_traits<char> > StrOstreamIt;

    StrVector Pattern(VECTOR_SIZE) ;

    StrVectorIt start, end, it ;

    StrOstreamIt outIt(cout, " ") ;

    start = Pattern.begin() ;   // location of first
                                      // element of Pattern

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

    //Initialize vector Pattern
    Pattern[0] = "K" ;
    Pattern[1] = "A" ;
    Pattern[2] = "L" ;

    //sort the contents of Pattern, required by next_permutation
    sort(start, end, less<string>()) ;

    // print content of Pattern
    cout << "Before calling next_permutation...\n" << "Pattern: " ;
    for(it = start; it != end; it++)
        cout << *it << " " ;
    cout << "\n\n" ;

    // Generate all possible permutations

    cout << "After calling next_permutation...." << endl ;
    while ( next_permutation(start, end, less<string>()) )
    {
        copy(start, end, outIt) ;
        cout << endl ;
    }
}

Program Output is:

Before calling next_permutation:
Pattern: A K L

After calling next_permutation:.
A L K
K A L
K L A
L A K
L K A
				

Back to the top

REFERENCES

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

Back to the top


APPLIES TO
The Standard C++ Library, when used with:
  Microsoft Visual C++ 4.2 Professional Edition
  Microsoft Visual C++ 4.2 Enterprise Edition
  Microsoft Visual C++ 5.0 Learning Edition

Back to the top

Keywords: 
kbcode kbhowto KB157869

Back to the top

Article Translations

 

Other Support Options

  • Need More Help?
    Contact a Support professional by E-mail, Online or Phone.
  • Customer Service
    For non-technical assistance with product purchases, subscriptions, online services, events, training courses, corporate sales, piracy issues, and more.
  • Newsgroups
    Pose a question to other users. Discussion groups and Forums about specific Microsoft products, technologies, and services.