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c++boostbitset

Can't understand the behaviour of dynamic_bitset

I am working on a Hill Climber Algorithm and I need to represent data as bitsets.

To sumarize my issue, I have written this piece of code:

#include <iostream>
#include <boost/dynamic_bitset.hpp>

void print(const boost::dynamic_bitset<> bitset)
{
    std::cout << bitset[0]; //bitset.at(0) - same result

}
int main()
{
    boost::dynamic_bitset<> myBitset(4, 10); // will be 1010
    std::cout << myBitset<<"\n";
    print(myBitset);
    return 0;
}

I can't understand why this prints

1010
0
Solution

  • As indicated in the comments, boost::dynamic_bitset indexes from the least-significant bit, i.e. the rightmost bit in the usual printed representation of a binary number. So bitset[0] is the zero on the far right of 1010, and the 1 that you expect to be printed is in fact bitset[3].