bitstring.cpp

// basic implementation of bitset using arrays
// might be useful as bitsets cannot be dynamically allocated during runtime

// testing / error handling / documentation PRs will be highly appreciated

#include <iostream>
#include <stdint.h>
#include <bitset>
#include <cstring>

using std::bitset;
using std::cout;

class bitstring
{
private:
	uint8_t *bit_array;
	int length;

public:
	// constructor
	bitstring(size_t size)
	{
		length = size / 8 + 1;
		bit_array = new uint8_t(length);
		memset(bit_array, 0, length);
	}

	// destructor
	~bitstring()
	{
		delete[] bit_array;
	}

	// setting the i'th bit
	void set(int i, bool value = true)
	{
		int index = i / 8;
		int n = i % 8;
		if (value == true)
			bit_array[index] |= 1 << n;
		else
			bit_array[index] &= !(1 << n);
	}

	// accessing the i'th bit
	int get(int i)
	{
		int index = i / 8;
		int n = i % 8;
		int bit = (bit_array[index] >> n) & 1U;
		return bit;
	}

	// toggling the i'th bit
	void toggle(int i)
	{
		int index = i / 8;
		int n = i % 8;
		bit_array[index] ^= 1 << n;
	}

	// accessing the i'th bit
	int operator[](int i)
	{
		return get(i);
	}

	// viewing the bit_array
	void show()
	{
		for (int i = length - 1; i > -1; i--)
		{
			cout << bitset<8>(bit_array[i]);
		}
		cout << '\n';
	}

	// resetting the entire bitstring
	void reset()
	{
		for (int i = 0; i < length; i++)
		{
			bit_array[i] = 0;
		}
	}
};

int main()
{
	// initializing bit_array of size 20:
	bitstring b = bitstring(20);

	// setting 4th and 5th  bit to true:
	b.set(4, true);
	// b.set(4) also valid
	b.set(3);

	// viewing the entire bitstring:
	b.show();

	// toggling the 4th bit
	b.toggle(3);

	// accessing the 4th and 5th bit:
	cout << "Bit 4 : " << b[3] << ", Bit 5 : " << b[4];
	// b.get(4) also valid

	// resetting the bitstring:
	b.reset();
}