reverse_copy(3C++)

Standard C++ Library
Copyright 1998, Rogue Wave Software, Inc.

NAME

reverse_copy

- Reverses the order of elements in a collection while copying them to a new collection.

SYNOPSIS

#include <algorithm>
template <class BidirectionalIterator, class OutputIterator>
OutputIterator reverse_copy (BidirectionalIterator first,

BidirectionalIterator last,
OutputIterator result);

DESCRIPTION

The reverse_copy algorithm copies the range [first, last) to the range [result, result + (last - first)) such that for any non- negative integer i < (last - first), the following assignment takes place:

∗(result + (last - first) -i) = ∗(first + i)

reverse_copy returns result + (last - first). The ranges [first, last) and [result, result + (last - first)) must not overlap.

COMPLEXITY

reverse_copy performs exactly (last - first) assignments.

EXAMPLE

//
// reverse.cpp
//

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

using namespace std;

int main ()

{

//
// Initialize a vector with an array of integers.
//

int arr[10] = { 1,2,3,4,5,6,7,8,9,10 };
vector<int> v(arr+0, arr+10);

//
// Print out elements in original (sorted) order.
//

cout << "Elements before reverse: " << endl << " ";
copy(v.begin(), v.end(),

ostream_iterator<int,char>(cout," "));

cout << endl << endl;

//
// Reverse the ordering.
//

reverse(v.begin(), v.end());

//
// Print out the reversed elements.
//

cout << "Elements after reverse: " << endl << " ";
copy(v.begin(), v.end(),

ostream_iterator<int,char>(cout," "));

cout << endl << endl;

cout << "A reverse_copy to cout: " << endl << " ";

reverse_copy(v.begin(), v.end(), <br> ostream_iterator<int,char>(cout, " "));

cout << endl;

return 0;

}

Program Output

Elements before reverse:

1 2 3 4 5 6 7 8 9 10

Elements after reverse:

10 9 8 7 6 5 4 3 2 1

A reverse_copy to cout:

1 2 3 4 5 6 7 8 9 10

WARNINGS

If your compiler does not support default template parameters, then you always need to supply the Allocator template argument. For instance, you need to write:

vector<int, allocator<int> >

instead of:

vector<int>

If your compiler does not support namespaces, then you do not need the using declaration for std.

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