How does copy constructor work?

Question

How does a copy constructor work in c++

Error 1 error C2064: term does not evaluate to a function taking 1 arguments c:\\users\\thuan\\dropbox\\homework\\css

Answer 1

it might help you to understand copy constructor

A copy constructor is used to declare and intilized an object from another obkect. whenever we have statement like demo d2-d1 (assume demo is class name and d1 is an already declared object of demo class),they make call to copy constructor defined in the class

for a class demo copy constructor is written as

demo(demo & d)
 {
  //copy constructor code;
 }

example:

#include
class demo
{
 int data;
public:
   demo(int x)
    {
      data=x;
    }

    demo(demo & d)
     {
       data=d.data;
        cout<<"copy constructor is called";
      }
    void show()
      {
        cout<<"data ="<