---

#define _CRT_SECURE_NO_WARNINGS
#include <iostream>
using namespace std;


class MyStr {
    int _count = 0;
    int length{ 0 };
    char* buff{ nullptr };
    static int count;
public:
    MyStr() : length(0), buff(nullptr) {
        _count = count++;
        cout << "  MyStr default constr. " << _count << endl;
    }
    MyStr(const char* init_val) : length(0), buff(nullptr){
        _count = count++;
        cout << "  MyStr( char * ) constr. " << _count << endl;;
        if ((init_val == nullptr) || (*init_val == '\0')) {
            return;
        }
        length = strlen(init_val);
        buff = new char[length + 1];
        strcpy(buff, init_val);        
    }
    MyStr(const MyStr& other) : length(0), buff(nullptr) {
        _count = count++;
        cout << "  MyStr( ) copy_ctor " << _count << endl;
        if (other.length == 0) {
            return;
        }
        this->length = other.length;
        this->buff = new char[length + 1];
        strcpy(buff, other.buff);
        
    }
    ~MyStr() {
        cout << "  MyStr( ) DTOR " << _count << endl;
        delete[] buff;
    }
    int size() { return length; }
    MyStr& operator= (const MyStr& other) {
        if (other.length == 0) {
            delete[] buff;
            buff = nullptr;
            length = 0;
        }
        else {
            delete[] buff;
            buff = nullptr;
            length = other.length;
            buff = new char[length + 1];
            strcpy(buff, other.buff);
        }
        return *this;
    }


    friend MyStr operator+(const MyStr& s1, const MyStr& s2);
    friend ostream& operator<< (ostream&, const MyStr&);
    char& operator[] (int index) {
        return buff[index];
    }
};
int MyStr::count = 0;
MyStr operator+(const MyStr& s1, const MyStr& s2) {
    MyStr ret;
    if ((s1.length == 0) && (s2.length == 0)) {
        
        return ret;
    }
    else if (s1.length == 0){
        return s2;
    }
    else if (s2.length == 0) {
        return s1;
    }
    else {
        ret.length = s1.length + s2.length;
        ret.buff = new char[ret.length+1];
        strcpy(ret.buff, s1.buff);
        strcat(ret.buff, s2.buff);

        return ret;

    }
    }



ostream& operator<< (ostream& os, const MyStr& s) {
    if (s.length == 0) {
        return os;
    }
    else {
        os << s.buff;
        return os;
    }
    
    return os;
}


int main() {
    string s = "Hello";
    cout << s.size() << endl;
    MyStr a = "\0";
    MyStr b = "\0";
    MyStr c;
    c = a + b;
    cout << c;
    /*
    MyStr c = a;
    ///////////////
    MyStr c2;
    c2 = a;
    ///////////////

   
    cout << c << endl;
    */
    return 0;
}