Decimal to binary.. what is wrong with this program

Question

import java.io.*;
class binary
{
public static void main(String args[])throws IOException
{
InputStreamReader ob=new InputStreamReader(System.in);
BufferedReader ob1=new BufferedReader(ob);
int i,n,a;
System.out.println("enter the number");
n=Integer.parseInt(ob1.readLine());
i=0;
while(n>0)
{
a=n%2;
n=n/2;
i++;
}
for(i=i-1;i>=0;i--)
{
System.out.print(i);
}
}
}

Answer 1

ok thanks