函数指针、类型别名与智能指针

// run in windows: std::system("pause")
#include <cstdlib>
#include <iostream>
#include <memory>
#include <functional>

using namespace std;
using namespace std::placeholders;

template <typename T>
using DeleteFunc = void(T*);

class Deleter;

template <typename T>
using DeleteMemberFunc = void(__thiscall Deleter::*)(T*)const;

// normal version
template <typename T>
inline void Delete(T* ptr)
{
    cout << "[delete] address: " << ptr << ", value: " << *ptr << endl;
    delete ptr;
}

// caller operator & static member function
class Deleter
{
public:
    Deleter() = default;
    ~Deleter() = default;
    Deleter(const Deleter&) = default;
    Deleter(Deleter&&) = default;
    Deleter& operator=(const Deleter&) = default;

    template <typename T>
    void operator()(T* ptr) const { Delete(ptr); }

    template <typename T>
    static void StaticDelete(T* ptr) { ::Delete(ptr); }
} deleter;

// std::function
function<DeleteFunc<int>> funcobj = &Delete<int>;
function<DeleteFunc<int>> static_funcobj = &Deleter::StaticDelete<int>;
function<DeleteFunc<int>> member_funcobj = bind(&Deleter::operator()<int> , &deleter, _1);

// lambda
auto lambda_delete = [](int* ptr) { Delete(ptr); };

using IntSPtr = shared_ptr<int>;
template <typename Func> using IntUPtr = unique_ptr<int, Func>;

int main(int argc, char* argv[])
{
    {
        DeleteMemberFunc<int> member_func = &Deleter::operator();

        IntSPtr s1 = make_shared<int>(10);
        IntSPtr s2(new int(11), &Delete<int>);
        IntSPtr s3(new int(12), Deleter());
        IntSPtr s4(new int(13), &Deleter::StaticDelete<int>);
        IntSPtr s5(new int(14), funcobj);
        IntSPtr s6(new int(15), static_funcobj);
        IntSPtr s7(new int(16), member_funcobj);
        IntSPtr s8(new int(17), lambda_delete);
        int* sp9 = new int(18);
        (deleter.*member_func)(sp9);

        unique_ptr<int> u1 = make_unique<int>(20);
        IntUPtr<DeleteFunc<int>*> u2(new int(21), &Delete<int>);
        IntUPtr<Deleter> u3(new int(22), Deleter());
        IntUPtr<DeleteFunc<int>*> u4(new int(23), &Deleter::StaticDelete<int>);
        IntUPtr<decltype(funcobj)> u5(new int(24), funcobj);
        IntUPtr<decltype(static_funcobj)> u6(new int(25), static_funcobj);
        IntUPtr<decltype(member_funcobj)> u7(new int(26), member_funcobj);
        IntUPtr<decltype(lambda_delete)> u8(new int(27), lambda_delete);
        int* up9 = new int(28);
        (deleter.*member_func)(up9);
    }

    std::system("pause");
    return 0;
}