RosettaCodeData/Task/Twos-complement/C++/twos-complement.cpp

#include <cstdint>
#include <iostream>
#include <iomanip>
#include <vector>
#include <bitset>

std::string to_hex(const int32_t number) {
    std::stringstream stream;
    stream << std::setfill('0') << std::setw(8) << std::hex << number;
    return stream.str();
}

std::string to_binary(const int32_t number) {
    std::stringstream stream;
    stream << std::bitset<16>(number);
    return stream.str();
}

int32_t twos_complement(const int32_t number) {
    return ~number + 1;
}

std::string to_upper_case(std::string str) {
    for ( char& ch : str ) {
        ch = toupper(ch);
    }
    return str;
}

int main() {
    std::vector<int32_t> examples = { 0, 1, -1, 42 };

    std::cout << std::setw(9) << "decimal" << std::setw(12) << "hex"
              << std::setw(17) << "binary" << std::setw(25) << "two's complement" << std::endl;
    std::cout << std::setw(6) << "-----------" << std::setw(12) << "--------"
              << std::setw(20) << "----------------" << std::setw(20) << "----------------" << std::endl;

    for ( const int32_t& example : examples ) {
        std::cout << std::setw(6) << example << std::setw(17) << to_upper_case(to_hex(example))
                  << std::setw(20) << to_binary(example) << std::setw(13) << twos_complement(example) << std::endl;
    }
}