sample7.cpp

Example how to use logical operations between arrays and bit-vectors

See also

bm::combine_and

bm::combine_and_sorted

bm::combine_sub

bm::combine_or

bm::combine_xor

bvsetalgebra.cpp

/*
Copyright(c) 2002-2017 Anatoliy Kuznetsov(anatoliy_kuznetsov at yahoo.com)
 
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
 
    http://www.apache.org/licenses/LICENSE-2.0
 
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
 
For more information please visit:  http://bitmagic.io
*/
 
/** \example sample7.cpp
 
  Example how to use logical operations between arrays and bit-vectors
 
  \sa bm::combine_and
  \sa bm::combine_and_sorted
  \sa bm::combine_sub
  \sa bm::combine_or
  \sa bm::combine_xor
 
  \sa bvsetalgebra.cpp
*/
 
/*! \file sample7.cpp
    \brief Example: set operations between bvector<> and arrays of integers.
*/
 
 
#include <iostream>
#include <algorithm>
#include <vector>
#include <list>
 
using std::vector;
using std::list;
 
// This example requires STL compatibility
#ifdef BM_NO_STL
# undef BM_NO_STL
#endif
#include "bm.h"
#include "bmalgo.h"
#include "bmundef.h" /* clear the pre-proc defines from BM */
 
using namespace std;
 
inline
void Print(unsigned n)
{
    cout << n << endl;;
}
 
// Utility template function used to print container
template<class T> void PrintContainer(T first, T last)
{
    if (first == last)
        cout << "<EMPTY SET>";
    else
        for(;first != last; ++first)
            cout << *first << ";";
    cout << endl;
}
 
int main(void)
{
    try
    {
        bm::bvector<>   bv;
        bv[10] = true;
        bv[100] = true;
        bv[10000] = true;
 
        // initialize unsorted, fairly random array for an experiment
        // it even allowes duplicates (see 12)
        //
        bm::bvector<>::size_type arr[] = {2, 10000, 5, 12, 255, 12, 300};
 
        
        cout << "Source set 1:";
        PrintContainer(bv.first(), bv.end());
        
        cout << "Source set 2:";
        PrintContainer(&arr[0], &arr[0] + (sizeof(arr)/sizeof(arr[0])));
        
        // AND operation between bit-vector and a plain array
        // expect one result: 10000
        // please note, that array in this case comes unsorted
        //
        bm::combine_and(bv, &arr[0], &arr[0] + (sizeof(arr)/sizeof(arr[0])));
        cout << "Result 1(AND): ";
        PrintContainer(bv.first(), bv.end());
 
        
        // re-initalize the bit-vector
        bv.clear();
        bv[10] = true;
        bv[100] = true;
        bv[10000] = true;
 
        // OR operation to merge bit-vector and array
        // please note that it naturally works as sort-unique for the array
        //
        bm::combine_or(bv, &arr[0], &arr[0] + (sizeof(arr)/sizeof(arr[0])));
        cout << "Result 2(OR): ";
        PrintContainer(bv.first(), bv.end());
 
        // sort the array, using STL sort method
        // combine operation on sorted arrays tend to be faster
        //
        std::sort(&arr[0], &arr[0] + (sizeof(arr)/sizeof(arr[0])));
        
        // AND on sorted array is faster
        //
        bm::combine_and_sorted(bv, &arr[0], &arr[0] + (sizeof(arr)/sizeof(arr[0])));
        cout << "Result 3(AND): ";
        PrintContainer(bv.first(), bv.end());
 
        // SUB (AND NOT or MINUS) also works faster on sorted input
        // the result should be an EMPTY set
        bm::combine_sub(bv, &arr[0], &arr[0] + (sizeof(arr)/sizeof(arr[0])));
        cout << "Result 4(MINUS): ";
        PrintContainer(bv.first(), bv.end());
 
    }
    catch(std::exception& ex)
    {
        std::cerr << ex.what() << std::endl;
        return 1;
    }
    
    
    return 0;
}