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

/*
void foo(int n)
{ if (n > 0)
  { foo (n/2);
    printf("%d", n%2);
  }
}
*/


void foo(int n)
{ int i=0, k = log2(n) + 1;
  int a[k];
  
  while (n>0)
  { a[i] = n%2;
    n = n/2;
    i++;
  }
 
  i--;
  while (i>=0)
  { printf("%d", a[i]);
    i--;
  }
}


int main()
{ int i=0;
  
  for (; i<10; i++)
  { printf("%d: ", i*i);
    foo(i*i);
    printf("\n");
  }

  return 0;
}