CONSTRUCTOR IN C++

#include<iostream.h>
#include<conio.h>
class sum
{
 int x;
 public:
//constructor
 sum()
 {
      x=89;
      cout<<"\nx = "<<x;
 }


 sum(int n)
 {
      x=n;
      cout<<"\nx = "<<x;
 }

  sum(sum &obj)
 {
      x=obj.x;
      cout<<"\nCopied Value =  "<<x;
 }

};


void main()
{
    clrscr();
    cout<<"\nDefault Constructor";
    sum s1;

    cout<<"\nParametrized Constructor";
    sum s2(34);

    cout<<"\nCopy Constructor";
    sum s3(s2);

    getch();

}