Read an integer from user and out it in binary format. Write a recursive function.

binary.c

#include <stdio.h>
#include <math.h>

int binary(int );
int main()
{
    int num;
    printf("Enter a num: ");
    scanf(" %i",&num);
    printf("The output in Binary is: %i \n",binary(num));
    return 0;
}
int binary(int x)
{
    if(x==0)
        return 0;
    int dig=log(x) / log(2);
    return (x%2)*pow(10,dig) + binary(x/2);
}