Question

1. White the class Trace with a copy constructor and an assignment operator, printing a short message in each. Use this class to demonstrate

   1. the difference between initialization

Trace t("abc");

Trace u = t;

and assignment.

Trace t("abc");

Trace u("xyz");

u = t;

2. the fact that all constructed objects are automatically destroyed.

3. the fact that the copy constructor is invoked if an object is passed by value to a

function.

4. the fact that the copy constructor is not invoked when a parameter is passed

by reference.

5. the fact that the copy constructor is used to copy a return value to the caller.

Programming language: C++

Requirement: please cover points 1-5.

Answer 1

#include<iostream>
using namespace std;

class Trace{
   string x;
   public:
       string getx()
       {
           return x;
       }
       void setx(string x)
       {
           this->x = x;
       }
       Trace()
       {
           x = "";
       }
       Trace(string x)
       {
           this->x = x;
       }
      
       Trace(Trace const &T)
       {
           cout<<"Copy Constructor invoked\n";
           this->x = T.x;
       }
      
       Trace operator=(Trace const &T)
       {
           cout<<"Assignment operator invoked\n";
           this->x = T.x;
       }

        ~Trace()

{

}

};

int main()
{
   Trace t("abc");
   Trace u = t;
   Trace v;
   v = t;
}

//output