Example in C++ of constructor, copy constructor and assignment operator calling

cpp_objects_constructor_and_assignment_operator_calling.cpp

#include <stdio.h>
#include <string>

using namespace std;

class myString {
  static int globalCounter;
  string str;
public:
  int counter;
  myString(const myString& s) : str(s.str), counter(s.counter) {
    printf("myString created using copy constructor\r\n");
    print();
  };
  myString(const string& s) : str(s), counter(globalCounter++) {
    printf("myString created\r\n");
    print();
  };
  ~myString() { printf("myString destroyed\r\n"); };
  myString& operator=(const myString& s) {
    str = s.str;
    counter = s.counter;
     printf("myString operator= called\r\n");
     return *this;
  };
  void print() {
    string msg = str;
    msg += " ";
    msg += to_string(static_cast<long long>(counter));
    msg += " my address: ";
    msg += to_string(reinterpret_cast<long long>(this));
    msg += "\r\n";
    printf(msg.c_str());
  };
};

int myString::globalCounter = 0;

myString fn(const char* str) {
  return myString(str);
}

void iReceiveAMyString(const myString) {
  printf("iReceiveAMyString called\r\n");
}

void main(){
  printf("vvvvvvv\r\n");
  {
    printf("Example with only one copy of myString class...\r\n");
    myString str = fn("hello");
    str.print();
  } // str will be destroyed when leaving scope, right here
  printf("^^^^^^^\r\n");

  printf("vvvvvvv\r\n");
  {
    printf("Even invoking as a constructor creates only one copy...\r\n");
    myString str(fn("hello"));
    str.print();
  } // str will be destroyed when leaving scope, right here
  printf("^^^^^^^\r\n");

  printf("vvvvvvv\r\n");
  {
    printf("When really copying into an uninitialized object copy constructor is finally used...\r\n");
    myString str(fn("hello"));
    printf("now we will assign str to str2\r\n");
    myString str2 = str;
    str.print();
    str2.print();
  } // str and str2 will be destroyed when leaving scope, right here
  printf("^^^^^^^\r\n");

  printf("vvvvvvv\r\n");
  {
    printf("What happens if we invoke function that doesn't use & operator?...\r\n");
    myString str(fn("hello"));
    iReceiveAMyString(str);
  } // str will be destroyed when leaving scope, right here
  printf("^^^^^^^\r\n");

  printf("vvvvvvv\r\n");
  {
    printf("When overwriting an object, assignment operator will be called...\r\n");
    myString str(fn("hello A"));
    myString str2(fn("hello B"));
    printf("let's print str2\r\n");
    str2.print();
    printf("now we will assign str to str2\r\n");
    str2 = str;
    printf("let's print str and after that str2\r\n");
    str.print();
    str2.print();
  } // str and str2 will be destroyed when leaving scope, right here
  printf("^^^^^^^\r\n");
}