Convert Decimal Number To Binary (C++)

#include<iostream.h>

#include<Math.h>

void main()
{
int k,t,w,i;
cin>>k;
i=0;
w=0;
while (k >0)
{ t=k%2;
k/=2;
w=w+ (t) * pow(10,i);
i++;
}
cout<<<"\n";