merge.cpp

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#include <algorithm>    // advance, copy, inplace_merge, merge
#include <functional>   // less
#include <iostream>     // cout
#include <iterator>     // back_inserter, ostream_iterator
#include <vector>       // vector
 
#include <examples.h>
 
 
int main ()
{
    typedef std::vector<int, std::allocator<int> > Vector;
 
    const Vector::value_type d1[] = { 1, 2, 3, 4};
    const Vector::value_type d2[] = { 11, 13, 15, 17, 12, 14, 16, 18};
 
    // Set up two vectors.
    Vector v1 (d1 + 0, d1 + sizeof d1 / sizeof *d1);
    Vector v2 (d1 + 0, d1 + sizeof d1 / sizeof *d1);
 
    // Set up four destination vectors.
    Vector v3 (d2 + 0, d2 + sizeof d2 / sizeof *d2);
    Vector v4 (v3);
    Vector v5 (v3);
    Vector v6 (v3);
 
    // Set up one empty vector.
    Vector v7;
 
    // Merge v1 with v2.
    std::merge (v1.begin (), v1.end (),
                v2.begin (), v2.end (), v3.begin ());
 
    // Now use comparator.
    std::merge (v1.begin (), v1.end (),
                v2.begin (), v2.end (), v4.begin (), std::less<int>());
 
    // Merge v5 in place.
    Vector::iterator mid = v5.begin ();
    std::advance (mid, 4);   // equivalent to mid += 4 but more generic
    std::inplace_merge (v5.begin (), mid, v5.end ());
 
    // Now use a comparator on v6.
    mid = v6.begin ();
    std::advance (mid, 4);   // equivalent to mid += 4 but more generic
    std::inplace_merge (v6.begin (), mid, v6.end (), std::less<int>());
 
    // Merge v1 and v2 to empty vector using insert iterator.
    std::merge (v1.begin (), v1.end (),
                v2.begin (), v2.end (), std::back_inserter (v7));
 
    // Copy all to cout.
    std::ostream_iterator<int, char, std::char_traits<char> >
        out (std::cout, " ");
 
    std::copy (v1.begin (), v1.end (), out);
    std::cout << '\n';
    std::copy (v2.begin (), v2.end (), out);
    std::cout << '\n';
    std::copy (v3.begin (), v3.end (), out);
    std::cout << '\n';
    std::copy (v4.begin (), v4.end (), out);
    std::cout << '\n';
    std::copy (v5.begin (), v5.end (), out);
    std::cout << '\n';
    std::copy (v6.begin (), v6.end (), out);
    std::cout << '\n';
    std::copy (v7.begin (), v7.end (), out);
    std::cout << '\n';
 
    // Merge v1 and v2 to cout.
    std::merge (v1.begin (), v1.end (), v2.begin (), v2.end (), out);
    std::cout << '\n';
 
    return 0;
}