# Config Parser

using K = key_type;
using T = value_type;

class config_base {
    config_base() {}
public:
    virtual T get(const K) = 0;
    virtual void set(const K, const K) = 0;
};

class PLC_confing_parser : virtual public config_base {
    PLC_confing_parser() {}
public:
    PLC_confing_parser &Instance() {
        static PLC_confing_parser c; // singleton
        return &c;
    }
    virtual T get(const K) override {}
    virtual void set(const K, const K) override {}
};

class VGA_confing_parser : virtual public config_base {
    VGA_confing_parser() {}
public:
    virtual T get(const K) override {}
    virtual void set(const K, const K) override {}
    // overwrite
    // override
};

// 匈牙利
class IConfigBase {
    // https://learn.microsoft.com/en-us/openspecs/windows_protocols/ms-dtyp/f8d4fe46-6be8-44c9-8823-615a21d17a61
    // WOW64
    //lost fit bit?
    // int * p = new int(42);
    // 
    // C89:
    // 
    // include <stdlib>
    // int* const p = malloc();
    // decltype(auto) p = malloc(); // int* const
    // auto p = malloc(); // int*
    // 45648949 *((int*)45648949)
    // (int*)p;
};

/// https://godbolt.org/z/aY4TGeceh
/// https://godbolt.org/z/xdxP5c5Gs](https://godbolt.org/z/5a3q7e9Y8)

// OSInfo
class IOSInfo {
    
};


// ...
////////////////////////////////////////

class config_base {
public:
    config_base() {}
    virtual int get(const int) {}
    virtual void set(const int, const int) {}
};

class PLC_confing_parser : virtual public config_base {
    /// ... 
};

class VGA_confing_parser : virtual public config_base {
public:
    VGA_confing_parser() {}
    virtual int get(const int) override {}
    virtual void set(const int, const int) override {}
};

int main() {
    VGA_confing_parser v;
    v.~VGA_confing_parser();
    v.get(1); // UB.
}

// https://godbolt.org/z/5PPfreM9q
// https://stackoverflow.com/questions/920500/what-is-the-purpose-of-cxa-pure-virtual
https://godbolt.org/z/GEKfzqe7c