`bit::vector` — Change All Elements

We have methods to set elements in a bit-vector to 1, reset them to 0, or flip them from 0 to 1 and vice versa. These methods can work on the entire bit-vector, on individual elements, or on blocks of contiguous elements.

1constexpr bit::vector &set(std::size_t i);
constexpr bit::vector &reset(std::size_t i);
constexpr bit::vector &flip(std::size_t i);

2constexpr bit::vector &set(std::size_t first,   std::size_t len);
constexpr bit::vector &reset(std::size_t first, std::size_t len);
constexpr bit::vector &flip(std::size_t first,   std::size_t len);

3constexpr bit::vector &set();
constexpr bit::vector &reset();
constexpr bit::vector &flip();

1: Sets, resets, or flips the value of the single element at index i.
2: Sets, resets, or flips the value of len elements starting at index first.
3: Sets, resets, or flips the elements’ values.

The len elements starting at first must fit in the valid range for the bit-vector.
Set the BIT_VERIFY flag at compile time to check this condition — any violation will cause the program to abort with a helpful message.

These methods return a reference to *this, so they can be chained with other calls.

Example

#include <bit/bit.h>
int main()
{
    std::size_t n = 4;
    std::size_t i = 0;

    bit::vector<> v(n);

    std::cout << "Setting ranges of elements to 1:\n";
    v.reset();
    std::cout << "Starting with vector of size " << v.size() << ": " << v << '\n';
    for (i = 0; i < v.size(); ++i) {
        std::size_t len, maxLen = v.size() - i + 1;
        for (len = 1; len < maxLen; ++len) {
            v.reset();
            std::cout << "Setting " << len << " element(s) starting at position: " << i << ": " << v.set(i, len) << '\n';
        }
    }
    std::cout << '\n';

    std::cout << "Setting ranges of elements to 0:\n";
    v.set();
    std::cout << "Starting with a vector of size " << v.size() << ": " << v << '\n';
    for (i = 0; i < v.size(); ++i) {
        std::size_t len, maxLen = v.size() - i + 1;
        for (len = 1; len < maxLen; ++len) {
            v.set();
            std::cout << "Resetting " << len << " element(s) starting at position: " << i << ": " << v.reset(i, len) << '\n';
        }
    }
    std::cout << '\n';

    std::cout << "Flipping ranges of elements from 1 to 0:\n";
    v.set();
    std::cout << "Starting with vector of size " << v.size() << ": " << v << '\n';
    for (i = 0; i < v.size(); ++i) {
        // v.set();
        std::size_t len, maxLen = v.size() - i + 1;
        for (len = 1; len < maxLen; ++len) {
            v.set();
            std::cout << "Flipping " << len << " element(s) starting at position: " << i << ": " << v.flip(i, len) << '\n';
        }
    }
    std::cout << '\n';

    return 0;
}

Output

Setting ranges of elements to 1:
Starting with a vector of size 4: [0 0 0 0]
Setting 1 element(s) starting at position: 0: [1 0 0 0]
Setting 2 element(s) starting at position: 0: [1 1 0 0]
Setting 3 element(s) starting at position: 0: [1 1 1 0]
Setting 4 element(s) starting at position: 0: [1 1 1 1]
Setting 1 element(s) starting at position: 1: [0 1 0 0]
Setting 2 element(s) starting at position: 1: [0 1 1 0]
Setting 3 element(s) starting at position: 1: [0 1 1 1]
Setting 1 element(s) starting at position: 2: [0 0 1 0]
Setting 2 element(s) starting at position: 2: [0 0 1 1]
Setting 1 element(s) starting at position: 3: [0 0 0 1]

Setting ranges of elements to 0:
Starting with a vector of size 4: [1 1 1 1]
Resetting 1 element(s) starting at position: 0: [0 1 1 1]
Resetting 2 element(s) starting at position: 0: [0 0 1 1]
Resetting 3 element(s) starting at position: 0: [0 0 0 1]
Resetting 4 element(s) starting at position: 0: [0 0 0 0]
Resetting 1 element(s) starting at position: 1: [1 0 1 1]
Resetting 2 element(s) starting at position: 1: [1 0 0 1]
Resetting 3 element(s) starting at position: 1: [1 0 0 0]
Resetting 1 element(s) starting at position: 2: [1 1 0 1]
Resetting 2 element(s) starting at position: 2: [1 1 0 0]
Resetting 1 element(s) starting at position: 3: [1 1 1 0]

Flipping ranges of elements from 1 to 0:
Starting with a vector of size 4: [1 1 1 1]
Flipping 1 element(s) starting at position: 0: [0 1 1 1]
Flipping 2 element(s) starting at position: 0: [0 0 1 1]
Flipping 3 element(s) starting at position: 0: [0 0 0 1]
Flipping 4 element(s) starting at position: 0: [0 0 0 0]
Flipping 1 element(s) starting at position: 1: [1 0 1 1]
Flipping 2 element(s) starting at position: 1: [1 0 0 1]
Flipping 3 element(s) starting at position: 1: [1 0 0 0]
Flipping 1 element(s) starting at position: 2: [1 1 0 1]
Flipping 2 element(s) starting at position: 2: [1 1 0 0]
Flipping 1 element(s) starting at position: 3: [1 1 1 0]

See Also