heap.cc

gcc-you can use this code to learn something about gcc, and inquire further into linux,

// Copyright (C) 2001 Free Software Foundation, Inc.
//
// This file is part of the GNU ISO C++ Library.  This library is free
// software; you can redistribute it and/or modify it under the
// terms of the GNU General Public License as published by the
// Free Software Foundation; either version 2, or (at your option)
// any later version.

// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without Pred the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License along
// with this library; see the file COPYING.  If not, write to the Free
// Software Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307,
// USA.

// 25.3.6 Heap operations [lib.alg.heap.operations]

#include <algorithm>
//#include <cmath>
#include <testsuite_hooks.h>

bool test = true;

const int A[] = {1, 11, 12, 3, 10, 6, 17, 4, 8, 2, 5, 13, 9, 15, 14, 16, 7};
const int B[] = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17};
const int C[] = {17, 16, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1};
const int N = sizeof(A) / sizeof(int);

// This functor has the equivalent functionality of std::geater<>,
// but there is no dependency on <functional> and it also tracks the
// number of invocations since creation.
class Gt
{
public:
    static int count() { return itsCount; }
    static void reset() { itsCount = 0; }

    bool
    operator()(const int& x, const int& y)
    {
        ++itsCount;
        return x > y; 
    }

private:
    static int itsCount;
};

int Gt::itsCount = 0;

// Exercise all of the heap functions for operator<.  The
// intermediate results between push_heap and pop_heap and
// make_heap and sort_heap are not checked (they could be).
void
test01()
{
    // sort array s1 using push_heap/pop_heap
    int s1[N];
    std::copy(A, A + N, s1);
    VERIFY(std::equal(s1, s1 + N, A));

    for (int i = 2; i <= N; ++i) {
        std::push_heap(s1, s1 + i);
    }
    for (int i = N; i >= 2; --i) {
        std::pop_heap(s1, s1 + i);
    }
    VERIFY(std::equal(s1, s1 + N, B));

    // sort array s2 using make_heap/sort_heap
    int s2[N];
    std::copy(A, A + N, s2);
    VERIFY(std::equal(s2, s2 + N, A));

    std::make_heap(s2, s2 + N);
    std::sort_heap(s2, s2 + N);
    VERIFY(std::equal(s2, s2 + N, B));
}

// Perform same tests as above but with the comparison predicate
// versions, and add complexity constraint checks.
void
test02()
{
    Gt gt;
//    const int logN = static_cast<int>(std::log(static_cast<double>(N)) + 0.5);
    const int logN = 3;

    int s1[N];
    std::copy(A, A + N, s1);
    VERIFY(std::equal(s1, s1 + N, A));

    for (int i = 2; i <= N; ++i) {
        std::push_heap(s1, s1 + i, gt);
        VERIFY(gt.count() <= logN);
        gt.reset();
    }

    for (int i = N; i >= 2; --i) {
        std::pop_heap(s1, s1 + i, gt);
        VERIFY(gt.count() <= 2 * logN);
        gt.reset();
    }

    VERIFY(std::equal(s1, s1 + N, C));

    // sort array s2 using make_heap/sort_heap
    int s2[N];
    std::copy(A, A + N, s2);
    VERIFY(std::equal(s2, s2 + N, A));

    std::make_heap(s2, s2 + N, gt);
    VERIFY(gt.count() <= 3 * N);
    gt.reset();

    std::sort_heap(s2, s2 + N, gt);
    VERIFY(gt.count() <= N * logN);

    VERIFY(std::equal(s2, s2 + N, C));
}

int
main(int argc, char* argv[])
{
    test01();
    test02();

    return !test;
}