Армянское Радио

#include <optional>
using ochar = std::optional<char>;

ochar a = 'a';
ochar b;

if(a) { std::cout << " a exists and contains " << *a << std::endl;}
if(!b) {std::cout << " b does not exist" << std::endl;}

#include <string>
#include <functional>
#include <iostream>
#include <optional>
 
// optional can be used as the return type of a factory that may fail
std::optional<std::string> create(bool b) {
    if (b)
        return "Godzilla";
    return {};
}
 
// std::nullopt can be used to create any (empty) std::optional
auto create2(bool b) {
    return b ? std::optional<std::string>{"Godzilla"} : std::nullopt;
}
 
// std::reference_wrapper may be used to return a reference
auto create_ref(bool b) {
    static std::string value = "Godzilla";
    return b ? std::optional<std::reference_wrapper<std::string>>{value}
             : std::nullopt;
}
 
int main()
{
    std::cout << "create(false) returned "
              << create(false).value_or("empty") << '\n';
 
    // optional-returning factory functions are usable as conditions of while and if
    if (auto str = create2(true)) {
        std::cout << "create2(true) returned " << *str << '\n';
    }
 
    if (auto str = create_ref(true)) {
        // using get() to access the reference_wrapper's value
        std::cout << "create_ref(true) returned " << str->get() << '\n';
        str->get() = "Mothra";
        std::cout << "modifying it changed it to " << str->get() << '\n';
    }
}

Queue()
{
head = NULL;
tail = NULL;
len = 0;
head->info.set_number(0);
}

#include <bitset>
#include <iostream>
#include <climits>

using namespace std;

int main() {
    int16_t temp;

    cout << "Введите произвольное число от -128 до 127: ";
    cin >> temp;
    
    char value=temp;

    cout << "Битовое представление числа " << value << " = " << bitset<sizeof(value) * CHAR_BIT>(value) << endl;
}