int number{};

    number = 15; //integer literal
    std::cout << number << std::endl;
    number = 0x0F; // 0x - and then you type your value {0F} in hexadecimal
    std::cout << number << std::endl;
    number = 0b1111; // 0b and then you type your value {0b} in binary
    std::cout << number << std::endl;

//Output is: 15 15 15