How to use the replace_if STL function in Visual C++ (156743)



The information in this article applies to:

  • The Standard C++ Library, when used with:
    • Microsoft Visual C++, 32-bit Enterprise Edition 4.2
    • Microsoft Visual C++, 32-bit Enterprise Edition 5.0
    • Microsoft Visual C++, 32-bit Enterprise Edition 6.0
    • Microsoft Visual C++, 32-bit Professional Edition 4.2
    • Microsoft Visual C++, 32-bit Professional Edition 5.0
    • Microsoft Visual C++, 32-bit Professional Edition 6.0
    • Microsoft Visual C++, 32-bit Learning Edition 6.0
    • Microsoft Visual C++ .NET (2003)
    • Microsoft Visual C++ .NET (2002)
    • Microsoft Visual C++ 2005 Express Edition

This article was previously published under Q156743

SUMMARY

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

MORE INFORMATION

Required Header

   <algorithm>
				
   template<class ForwardIterator, class Predicate, class Type> inline
   void replace_if(ForwardIterator first,

                   ForwardIterator last,
                   Predicate pred,
                   const Type& value)
				
NOTE: The class/parameter names in the prototype do not match the version in the header file. Some have been modified to improve readability.

Description

The replace_if algorithm replaces all elements from the range [first, last) that cause the predicate to return true with value.

Sample Code

NOTE: In the first line of the sample code section, /GX is equivalent to /EHsc in Visual C++ .NET or Visual C++ 2005 and is set by default.
////////////////////////////////////////////////////////////////////// 
// 
// Compile options needed: /GX
// 
// replace_if.cpp : Illustrates how to use the replace_if function.
// 
// Functions:
// 
//    replace_if - Replace all elements from the sequence that
//                 satisfies a predicate with a specified value.
// 
// 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 <algorithm>
#include <functional>

#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 integers
    typedef vector<int, allocator<int> > IntVector ;

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

    IntVector Numbers(VECTOR_SIZE) ;   //vector containing numbers

    IntVectorIt start, end, it ;

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

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

    //Initialize vector Numbers
    Numbers[0] = 10 ;
    Numbers[1] = 20 ;
    Numbers[2] = 10 ;
    Numbers[3] = 15 ;
    Numbers[4] = 12 ;
    Numbers[5] = 7 ;
    Numbers[6] = 9 ;
    Numbers[7] = 10 ;

    cout << "Before calling replace_if" << endl ;

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

    // replace all elements from Numbers that are <= 10 with 4
     replace_if(start, end, bind2nd(less_equal<int>(), 10), 4 ) ;

    cout << "After calling replace_if" << endl ;

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

}
				
Program Output is:
Before calling replace_if
Numbers { 10 20 10 15 12 7 9 10  }

After calling replace_if
Numbers { 4 20 4 15 12 4 4 4  }
				

REFERENCES

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

Modification Type:MinorLast Reviewed:1/13/2006
Keywords:kbcode kbinfo KB156743 kbAudDeveloper