INFO: STL Sample for the inplace_merge Function (156901)

MORE INFORMATION

Required Header

   <algorithm>
				

Prototype

   template<class BidirectionalIterator> inline

       void inplace_merge(BidirectionalIterator first,
                          BidirectionalIterator middle,
                          BidirectionalIterator last)
				

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 inplace_merge algorithm merges two sorted sub-sequences: [first..middle) and [middle..last) in place into a single sorted sequence [first..last). This version assumes that the ranges [first..middle) and [middle..last) are sorted using operator<. If both ranges contain equal values, the value from the first range will be stored first.

Sample Code

////////////////////////////////////////////////////////////////////// 
// 
// Compile options needed: /GX
// 
// inplace_merge.cpp : Illustrates how to use the inplace_merge
//                     function.
// 
// Functions:
// 
//   inplace_merge : Merge two sorted sub-sequences in place into a
//                   single sorted list.
// 
//   begin - Returns an iterator that points to the first element in a
//           sequence.
// 
//   end - Returns an iterator that points one past the end of a sequence.
// 
// 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 <functional>
#include <vector>

#if _MSC_VER > 1020   // if VC++ version is > 4.2
   using namespace std;  // std c++ libs implemented in std
   #endif

void main()

{

    const int VECTOR_SIZE = 8 ;

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

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

    IntVector Numbers(VECTOR_SIZE) ;

    IntVectorIt start, end, it ;

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

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

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

    cout << "Before calling inplace_merge\n" << endl ;

    // print content of Numbers
    cout << "Numbers { " ;
    for(it = start; it != end; it++)
        cout << *it << " " ;
    cout << " }\n" << endl ;

    //merge the elements of Numbers in place
    inplace_merge(start, start + 3, end) ;

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

    // print content of Numbers
    cout << "Numbers { " ;
    for(it = start; it != end; it++)
        cout << *it << " " ;
    cout << " }\n" << endl ;

}
				

Program Output is: Before calling inplace_merge

Numbers { 4 10 70 10 30 69 96 100  }

After calling inplace_merge

Numbers { 4 10 10 30 69 70 96 100  }