heap_ops.cpp

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#include <algorithm>    // for copy, make_heap, pop_heap, push_heap
#include <functional>   // for less
#include <iostream>     // for cout
#include <iterator>     // for ostream_iterator
#include <vector>       // for vector
 
#include <examples.h>
 
 
template <class charT, class Traits, class T, class Allocator>
void print_vector (std::basic_ostream<charT, Traits> &strm,
                   const std::vector<T, Allocator>   &v)
{
    std::copy (v.begin (), v.end (),
               std::ostream_iterator<T, charT, Traits> (strm, " "));
 
    strm << std::endl;
}
 
 
int main ()
{
    typedef std::vector<int, std::allocator<int> > Vector;
 
    const Vector::value_type d1[] = { 1, 2, 3, 4 };
    const Vector::value_type d2[] = { 1, 3, 2, 4 };
 
    // Set up two vectors.
    Vector v1 (d1 + 0, d1 + sizeof d1 / sizeof *d1);
    Vector v2 (d2 + 0, d2 + sizeof d2 / sizeof *d2);
 
    // Make heaps.
    std::make_heap (v1.begin (), v1.end ());
    std::make_heap (v2.begin (), v2.end (), std::less<int>());
 
    // v1 = (4, x, y, z)  and  v2 = (4, x, y, z)
 
    // Note that x, y and z represent the remaining values in the
    // container (other than 4).  The definition of the heap and heap
    // operations  does not require any particular ordering
    // of these values.
 
    // Copy both vectors to cout.
    print_vector (std::cout, v1);
    print_vector (std::cout, v2);
 
    // Now let's pop.
    std::pop_heap (v1.begin (), v1.end ());
    std::pop_heap (v2.begin (), v2.end (), std::less<int>());
 
    print_vector (std::cout, v1);
    print_vector (std::cout, v2);
 
    // And push.
    std::push_heap (v1.begin (), v1.end ());
    std::push_heap (v2.begin (), v2.end (), std::less<int>());
 
    print_vector (std::cout, v1);
    print_vector (std::cout, v2);
 
    // Now sort those heaps.
    std::sort_heap (v1.begin (), v1.end ());
    std::sort_heap (v2.begin (), v2.end (), std::less<int>());
 
    print_vector (std::cout, v1);
    print_vector (std::cout, v2);
 
    return 0;
}