remove_copy (STL Sample)

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

Required Header:
<algorithm>

template<class ForwardIterator, class OutputIterator, class Type> inline
     OutputIterator remove_copy(ForwardIterator first, ForwardIterator last, 
     OutputIterator result, const T& 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 remove_copy algorithm copies all elements from the range (first, last) to the range starting at result, skipping any element that matches value. It returns an iterator positioned immediately after the last new element.

Sample Code:

//////////////////////////////////////////////////////////////////////
//
// Compile options needed: /GX
//
// remove_copy.cpp : Illustrates how to use the remove_copy function.
//
// Functions:
//
//   remove_copy - copy the elements of a sequence to another sequence
//                 eliminating any elements that match value.
//   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.
//////////////////////////////////////////////////////////////////////

// disable warning C4786: symbol greater than 255 character,
// okay to ignore
#pragma warning(disable: 4786)

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

using namespace std;


void main()
{
   const int MAX_ELEMENTS = 8 ;

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

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

   //vector containing numbers
   IntVector Numbers(MAX_ELEMENTS), Result(MAX_ELEMENTS) ;

   IntVectorIt start, end, it, last, resultIt ;

   //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 ;

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

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

   resultIt = Result.begin() ; // location of first
                               // element of Result

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

   // copy all elements from Numbers to Result
   // skipping any item that equals 10
   last = remove_copy(start, end, resultIt, 10) ;

   //print number of elements copied to Result
   cout << "Total number of elements copied to Result = "
      << last - resultIt << endl ;

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

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

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

 

Program Output is:

Numbers { 10 20 10 15 12 7 9 10  }

Total number of elements copied to Result = 5
Result { 20 15 12 7 9 0 0 0  }