STL Sample for the Predicate Persion of upper_bound Function

• The Standard C++ Library included with: - Microsoft Visual C++, 32-bit Edition, version 4.2

SUMMARY

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

MORE INFORMATION

Required Header

   <algorithm>

Prototype

   template<class ForwardIterator, class T, class Compare> inline
       ForwardIterator upper_bound(ForwardIterator first,
                                   ForwardIterator last,
                                   const T& value,
                                   Compare compare)

Description

The upper_bound algorithm returns the last location in the sequence that value can be inserted such that the order of the sequence [first..last) is maintained.

upper_bound returns an iterator positioned at the location that value can be inserted in the range [first..last), or returns last if no such position exists.

This version assumes the range [first..last) is sorted sequentially using the compare function.

Sample Code

//////////////////////////////////////////////////////////////////////
//
// Compile options needed: /GX
//
// upper_bound.cpp : Illustrates how to use the predicate version
//                   of the upper_bound function.
//
// Functions:
//
//    upper_bound : Return the upper bound within a range.
//
// 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

#include <iostream>
#include <algorithm>
#include <functional>
#include <vector>

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, location ;

    // 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

    //sort Numbers using the function object less<int>()
    //upper_bound assumes that Numbers is sorted
    //using the "compare" (less<int>() in this case)
    //function
    sort(start, end, less<int>()) ;

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

    //return the highest location at which 10 can be inserted
    // in Numbers
    location = upper_bound(start, end, 10, less<int>()) ;

    cout << "Last location  for element 10 in Numbers is: "
        << location - start << endl ;
}

Numbers { 4 10 10 30 69 70 96 100 }

Last location for element 10 in Numbers is: 3

REFERENCES

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