dec2hex

#include <iostream>

int main()
{
    int decimalNum = 0;
    int hexPart = 0;
    char hexChar = 0;
    char hexH = 0;
    char hexL = 0;

    do
    {
        std::cout << "Enter decimal number from 0 to 255\n";
        std::cin >> decimalNum;
        if (decimalNum < 0 || decimalNum > 255)
        {
            std::cout << "Error: Out of range 0..255, try again!\n";
        }
    } while (decimalNum < 0 || decimalNum > 255);

    while (decimalNum > 0)
    {
        hexPart = decimalNum % 16;

        if (hexPart < 10)
        {
            hexChar = '0' + hexPart;
        }
        else
        {
            hexChar = 'A' + hexPart - 10;
        }

        std::cout << "hexChar=" << hexChar << std::endl;
        decimalNum / 16 == 0 ? hexH = hexChar : hexL = hexChar;

        decimalNum /= 16;
    }
    std::cout << "HEX: " << hexH << hexL << "\n";
}