decimal to Binary conversion

#include<stdio.h>
int main()
{
    int num,r,j,i=0;
    int bin[1000];
    scanf("%d",&num);
    while(num!=0)
    {
        r=num%2;
        num=num/2;
        bin[i]=r;
        i++;
    }
    for(j=i-1;j>=0;j--)
    {
        printf("%d",bin[j]);
    }
    return 0;
}