swap_ranges

Algorithm

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• Example
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Exchanges a range of values in one location with those in another.

None

#include <algorithm>
template <class ForwardIterator1, class ForwardIterator2>
  ForwardIterator2 
    swap_ranges (ForwardIterator1 first1,
                 ForwardIterator1 last1,
                 ForwardIterator2 first2);

The swap_ranges algorithm exchanges corresponding values in two ranges, in the following manner:

For each non-negative integer n < (last - first), the function exchanges *(first1 + n) with *(first2 + n)). After completing all exchanges, swap_ranges returns an iterator that points to the end of the second container (in other words, first2 + (last1 -first1)). The result of swap_ranges is undefined if the two ranges [first, last) and [first2, first2 + (last1 - first1)) overlap.

//
// swap.cpp
//
#include <vector>
#include <algorithm>
#include <iostream>
using namespace std;

int main()
{
int d1[] = {6, 7, 8, 9, 10, 1, 2, 3, 4, 5};
// Set up a vector
vector<int> v(d1+0,d1 + 10);

// Output original vector
cout << "For the vector: ";
copy(v.begin(),v.end(),
     ostream_iterator<int,char>(cout," "));

// Swap the first five elements with the last five elements
swap_ranges(v.begin(),v.begin()+5, v.begin()+5);
// Output result
cout << endl << endl
<< "Swapping the first five elements "
<< "with the last five gives: "
<< endl << "     ";
copy(v.begin(),v.end(),
     ostream_iterator<int,char>(cout," "));
return 0;
}

Program Output

For the vector: 6 7 8 9 10 1 2 3 4 5
Swapping the first five elements with the last five gives:
1 2 3 4 5 6 7 8 9 10
Swapping the first and last elements gives:
10 2 3 4 5 6 7 8 9 1

If your compiler does not support default template parameters, 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.

iter_swap, swap