---

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

class MyStr { 
    int length{ 0 };
    char* buff{ nullptr };
public:
    MyStr() : length(0), buff(nullptr) { 
        cout << "  MyStr default constr.\n";
    }
    MyStr(const char* init_val) { 
        if (init_val != nullptr && *init_val != '\0') { 
            length = strlen(init_val);
            buff = new char[length + 1];
            strcpy(buff, init_val);
        }
        cout << "  MyStr( char * ) constr.\n";
    }
    MyStr(const MyStr& other) { 
        if (other.length != 0) {
            this->length = other.length;
            buff = new char[length + 1];
            strcpy(buff, other.buff);
        }
    }
    ~MyStr() { // Destructor must be virtual if the class has at least one virtual function
        cout << "  MyStr destr.\n";
        delete[] buff;
        // delete[] buff; - Will throw an exception if called twice
    }

    int size() { return length; }

    MyStr& operator= (const MyStr& rhs) { // const MyStr& rhs = m_DerivedFromMyStr
        if (this == &rhs)
            return *this;
        delete[] buff;
        length = rhs.length;
        if (rhs.length > 0) {
            buff = new char[length + 1];
            strcpy(buff, rhs.buff);
        }
        return *this;
    }


    friend MyStr operator+(const MyStr& s1, const MyStr& s2);
    friend ostream& operator<< (ostream&, const MyStr&);
    char& operator[] (int index) {
        return this->buff[index];
    }
};

MyStr operator+(const MyStr& s1, const MyStr& s2) { // Concatenation operator that accepts two instances of MyStr class
    MyStr res; // Create the result instance of MyStr class
    res.length = s1.length + s2.length; // Assign s1 and s2 instances length to result instance length
    res.buff = new char[res.length + 1]; // Create a new buffer on result instance
    if (s1.buff) strcpy(res.buff, s1.buff); else res.buff[0] = '\0'; // Copy s1 buffer to result buffer if not empty, else make result buffer nullptr
    if (s2.buff) strcat(res.buff, s2.buff); // Append s2 buffer to result buffer if not empty
    return res;
}

ostream& operator<< (ostream& os, const MyStr& s) {
    return os;
}


int main() {
    MyStr a; //= "Hello ";
    MyStr b = "World!";
    ///////////////
    MyStr c = a;

    //int j = 10;
    //int& i = j; // int* const pi = &j; i <=> *pi;
    ///////////////
    MyStr c2{ "10" };
    //c2 = a;
    ///////////////

    c = a + b;
    cout << c << endl;
    cout << c2 << endl;
    cout << b.size() << endl;

    return 0;

}