INFO: STL Sample for the replace_if Function

ID: Q156743

The information in this article applies to:

The Standard C++ Library, used with:
- Microsoft Visual C++, 32-bit Editions, versions 4.2, 5.0, 6.0

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


////////////////////////////////////////////////////////////////////// 
// 
// 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.

Additional query words: STL STLSample remove_if

Keywords : kbcode kbVC420 kbVC500 kbVC600 kbDSupport STLIss
Version : winnt:4.2,5.0,6.0
Platform : winnt
Issue type : kbinfo