Урок 5 совершенный способ

kutuzzzov

Jun 13th, 2023

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#include <iostream>
#include <string>
#include <string_view>
#include <type_traits>
#include <utility>
#include <memory>
using namespace std;
class AnyStorageBase {
public:
virtual ~AnyStorageBase() {};
virtual void Print(ostream& out) const = 0;
};
template <typename T>
class AnyStorage : public AnyStorageBase {
public:
template <typename S>
AnyStorage(S&& data)
: data_(forward<S>(data)){
}
void Print(ostream& out) const override {
out << data_;
}
private:
T data_;
};
class Any {
public:
template <typename S>
Any(S&& type) {
using Initial = std::remove_reference_t<S>;
ptr_ = make_unique<AnyStorage<Initial>>(forward<S>(type));
}
void Print(ostream& out) const {
ptr_->Print(out);
}
private:
unique_ptr<AnyStorageBase> ptr_;
};
class Dumper {
public:
Dumper() {
std::cout << "construct"sv << std::endl;
}
~Dumper() {
std::cout << "destruct"sv << std::endl;
}
Dumper(const Dumper&) {
std::cout << "copy"sv << std::endl;
}
Dumper(Dumper&&) {
std::cout << "move"sv << std::endl;
}
Dumper& operator=(const Dumper&) {
std::cout << "= copy"sv << std::endl;
return *this;
}
Dumper& operator=(Dumper&&) {
std::cout << "= move"sv << std::endl;
return *this;
}
};
ostream& operator<<(ostream& out, const Any& arg) {
arg.Print(out);
return out;
}
ostream& operator<<(ostream& out, const Dumper&) {
return out;
}
int main() {
Any any_int(42);
Any any_string("abc"s);
// операция вывода Any в поток определена чуть выше в примере
cout << any_int << endl << any_string << endl;
Any any_dumper_temp{Dumper()};
Dumper auto_dumper;
Any any_dumper_auto(auto_dumper);
}

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