reverse_copy (STL Sample)

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

Required Header:
<algorithm>

template<class BidirectionalIterator, class OutputIterator> inline
     OutputIterator reverse_copy(BidirectionalIterator first,
     BidirectionalIterator last,
     OutputIterator result)

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 reverse_copy algorithm reverses the order of the elements in the range [first, last) and copies the result into a sequence of the same size starting at result. It returns an iterator positioned immediately after the last new element in the resulting sequence.

Sample Code:

//////////////////////////////////////////////////////////////////////
//
// Compile options needed: /GX
//
// reverse_copy.cpp : Illustrates how to use the reverse_copy function.
//
// Functions:
//
//    reverse_copy - Reverse a sequence, copy the results to another
//                   same-sized sequence.
//
//////////////////////////////////////////////////////////////////////

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

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

using namespace std ;

void main()
{
    const int VECTOR_SIZE = 8 ;

    // Define a template class vector of strings
    typedef vector<string> StrVector ;

    //Define an iterator for template class vector of strings
    typedef StrVector::iterator StrVectorIt ;

    StrVector Tongue_Twister(VECTOR_SIZE) ;
    StrVector Reversed_Twister(VECTOR_SIZE) ;

    StrVectorIt start, end, it, RTstart, RTend ;

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

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

    RTstart = Reversed_Twister.begin() ; // location of first
                                         // element of Reversed_Twister

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

    //Initialize vector Tongue_Twister
    Tongue_Twister[0] = "she" ;
    Tongue_Twister[1] = "sells" ;
    Tongue_Twister[2] = "sea" ;
    Tongue_Twister[3] = "shells" ;
    Tongue_Twister[4] = "by";
    Tongue_Twister[5] = "the";
    Tongue_Twister[6] = "sea" ;
    Tongue_Twister[7] = "shore" ;

    cout << "Before calling reverse_copy \n" << endl ;

    // print content of Tongue_Twister
    cout << "Try this Tongue Twister: " ;
    for(it = start; it != end; it++)
        cout << *it << " " ;
    cout << "\n\n" ;

    // reverse the items in the vector Tongue_Twister
    // and copy the results to Reversed_Twister
     reverse_copy(start, end, RTstart) ;

     cout << "After calling reverse_copy: \n"
         << endl ;

    // print content of Tongue_Twister
    cout << "Tongue_Twister: " ;
    for(it = start; it != end; it++)
        cout << *it << " " ;
    cout << "\n\n" ;

    // print content of Reversed_Twister
    cout << "Now try the reversed Tongue Twister: " ;
    for(it = RTstart; it != RTend; it++)
        cout << *it << " " ;
    cout << "\n\n" ;

}

 

Program Output is:

Before calling reverse_copy

Try this Tongue Twister: she sells sea shells by the sea shore

After calling reverse_copy:

Tongue_Twister: she sells sea shells by the sea shore

Now try the reversed Tongue Twister: shore sea the by shells sea sells she