#include <iostream>
#include <cassert>
#include <cstdint>

using namespace std;

char nibble_to_hex(uint8_t i)
{
    assert(0x0 <= i && i <= 0xf);
    const char digits[] = "0123456789abcdef";
    return digits[i];
}

uint8_t get_lower_nibble(uint8_t byte)
{
    return byte & 0x0F;
}

uint8_t get_upper_nibble(uint8_t byte)
{
    return byte >> 4;
}

void print_in_hex(uint8_t byte)
{
    cout << nibble_to_hex(get_upper_nibble(byte))
        << nibble_to_hex(get_lower_nibble(byte));
}

const uint8_t* as_bytes(const void* data)
{
    return reinterpret_cast<const uint8_t*>(data);
}

void print_in_hex(const void* data, size_t size)
{
    const uint8_t* bytes = as_bytes(data);
    for (size_t i = 0; i < size; i++)
    {
        print_in_hex(bytes[i]);
        if ((i + 1) % 16 == 0)
        {
            cout << '\n';
        }
        else
        {
            cout << ' ';
        }
    }
}

void print_in_binary(uint8_t byte)
{
    for (int bit = 7; bit >= 0; --bit)
    {
        cout << ((byte & (1 << bit)) ? '1' : '0');
    }
}

void print_in_binary(const void* data, size_t size)
{
    const uint8_t* bytes = as_bytes(data);
    for (size_t i = 0; i < size; i++)
    {
        print_in_binary(bytes[i]);
        if ((i + 1) % 4 == 0)
        {
            cout << '\n';
        }
        else
        {
            cout << ' ';
        }
    }
}

int main()
{
    for (uint8_t i = 0; i < 16; i++)
    {
        assert(nibble_to_hex(i) == (i < 10 ? '0' + i : 'a' + (i - 10)));
    }

    uint8_t byte = 0xab;

    cout << "Hex: ";
    print_in_hex(byte);
    cout << '\n';

    cout << "Binary: ";
    print_in_binary(byte);
    cout << '\n';

    uint32_t u32 = 0x42;
    cout << "u32 bytes in hex: ";
    print_in_hex(&u32, sizeof(u32));
    cout << '\n';

    cout << "u32 bytes in binary: ";
    print_in_binary(&u32, sizeof(u32));
    cout << '\n';

    return 0;
}