op over (int * obj) w/o return

#include<conio.h>
#include<iostream>
using namespace std;
class vector
{
	private :int i,j,k;
	public :void read()
			{
				cout<<"Enter coefficients of i,j,k:";
				cin>>i>>j>>k;
			}
			void display()
			{
				cout<<i<<"i+ "<<j<<"j+ "<<k<<"k"<<endl;
			}
			friend void operator*(int x,vector &a)
			{
				a.i=x*a.i;
				a.j=x*a.j;
				a.k=x*a.k;
			}
};
int main()
{
	vector v1;
	v1.read();
	v1.display();
	4*v1;
	v1.display();
	return 0;
}