#include <library.h>

int two_to_power(int x)
{ if (x == 0)
    return 1;
  return 2 * two_to_power(x - 1); }

void test(int N, int end)
{ if (N <= end)
  { print("two to the power of ");
    print(N);
    print(" = ");
    print(two_to_power(N));
    new_line();
    test(N+1, end); } }

int main()
{ test(0, 40); }