Overload Assignment Operator using Constructor and Copy Constructor

#include<iostream.h>
#include<conio.h>
class vector
{
int *v;
int size;
public:
vector(int vector_size)
{
size=vector_size;
v=new int[vector_size];
}
vector(vector &v2);
~vector()
{
delete v;
}
int &elem(int i)
{
if(i>=size)
{
cout<<endl<<"Error:out of range";
//return -1;
}
return v[i];
}
void show();
};
vector::vector(vector &v2)
{
cout<<"\n copy constructor invoked";
size=v2.size;
v=new int[v2.size];
for(int i=0;i<v2.size;i++)
v[i]=v2.v[i];
}
void vector::show()
{
for(int i=0;i<size;i++)
cout<<elem(i)<<",";
}
void main()
{
int i;
clrscr();
vector v1(5),v2(5);
for(i=0;i<5;i++)
v2.elem(i)=i+1;
v1=v2;
vector v3=v2;
cout<<"\n vector v1:";
v1.show();
cout<<"\nvector v2:";
v2.show();
cout<<"\n vector v3:";
v3.show();
getch();
}