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Questions tagged [bitset]

A collection of bits organized as an array of bits, in which each bit can be accessed separately. For C++ bitsets, prefer the tag std-bitset

A collection of bits organized as an array of bits, in which each bit can be accessed separately.

Usage guidelines:

Related tags, with slighly differences:

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Why is the std::bitset<8> variable unable to handle 11111111?

Why is this program showing the following output ? #include ... { std::bitset<8> b1(01100100); std::cout< b2(11111111); std::cout<
Shravan
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Which bitset implementation should I use for maximum performance?

I'm currently trying to implement various algorithms in a Just In Time (JIT) compiler. Many of the algorithms operate on bitmaps, more commonly known as bitsets. In C++ there are various ways of implementing a bitset. As a true C++ developer, I…
Man of One Way
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How to implement a bitset in C?

I have been using the Bitset class in Java and I would like to do something similar in C. I suppose I would have to do it manually as most stuff in C. What would be an efficient way to implement? byte bitset[] maybe bool bitset[] ?
David Robles
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Get all Indexes of the set bits in a BitSet

I'm looking for a fast algorithm with gives me all the indexes of the set bits in a BitSet object. This is slow: BitSet bitSet = ... Collection indexes = new ArrayList(bitSet.cardinality()); int nextSetBit =…
myborobudur
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Java BitSet and byte[] usage

I have this application where I should use BitSet class heavily and write to a file bit by bit. I know I can't write bits to a file, so first I convert the BitSet object to byte array and write as byte array. But the problem is since BitSet class…
gmnnn
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Construct bitset from array of integers

It's easy to construct a bitset<64> from a uint64_t: uint64_t flags = ...; std::bitset<64> bs{flags}; But is there a good way to construct a bitset<64 * N> from a uint64_t[N], such that flags[0] would refer to the lowest 64 bits? uint64_t…
Barry
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Why there isn't a single bit data type in C/C++?

For bool, it's 8 bit while has only true and false, why don't they make it single bit. And I know there's bitset, however it's not that convenient, and I just wonder why?
iloahz
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Is it possible to convert bitset<8> to char in c++?

I have bitset<8> v8 and its value is something like "11001101", how can I convert it to char? I need a single letter. Like letter "f"=01100110. P.S. Thanks for help. I needed this to illustrate random errors in bits. For example without error f, and…
Van
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How do I convert bitset to array of bytes/uint8?

I need to extact bytes from the bitset which may (not) contain a multiple of CHAR_BIT bits. I now how many of the bits in the bitset I need to put into an array. For example, the bits set is declared as std::bitset < 40> id; There is a separate…
dubnde
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Convert Byte Array into Bitset

I have a byte array generated by a random number generator. I want to put this into the STL bitset. Unfortunately, it looks like Bitset only supports the following constructors: A string of 1's and 0's like "10101011" An unsigned long. (my byte…
Unknown
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Large (0,1) matrix multiplication using bitwise AND and popcount instead of actual int or float multiplies?

For multiplying large binary matrices (10Kx20K), what I usually to do is to convert the matrices to float ones and perform float matrix multiplication as integer matrix multiplication is pretty slow (have a look at here). This time though, I'd need…
NULL
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Why is BitSet not Iterable?

BitSet has a stream() method but it does not implement the Iterable interface like other types that provide this method. Is there a specific reason for this?
Raffi Khatchadourian
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Concatenate boost::dynamic_bitset or std::bitset

what is the best way to concatenate 2 bitsets? For example i've got boost::dynamic_bitset<> test1( std::string("1111") ); boost::dynamic_bitset<> test2( std::string("00") ); they should be concatenated into a thrid Bitset test3 which then…
MOnsDaR
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Why does std::bitset expose bits in little-endian fashion?

When I use std::bitset::bitset( unsigned long long ) this constructs a bitset and when I access it via the operator[], the bits seems to be ordered in the little-endian fashion. Example: std::bitset<4> b(3ULL); std::cout << b[0] << b[1] << b[2]…
legends2k
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Converting Between std::bitset and std::vector

I have a std::bitset but now I want to use an STL algorithm on it. I could have used std::vector instead, but I like std::bitset's constructor and I want std::bitset's bitwise operations. Do I have to go through a loop and stuff everything in…
Jonathan Mee
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