STL Sample for the replace_if 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 replace_if STL function in Visual C++.

MORE INFORMATION

Required Header

   <algorithm>

Prototype

   template<class ForwardIterator, class Predicate, class Type> inline
   void replace_if(ForwardIterator first,
                   ForwardIterator last,
                   Predicate pred,
                   const Type& value)

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

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

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.