#include <library.h>

int find_sqrt(int a, int b, int x)  // want square root of x, given
                                    // that it will be between a and b
{ const int mid = (a+b)/2;
  cout << "my guess is " << mid << "\n";

  if (b <= a)      // this lets it give a good answer when an exact
    return mid;    // does not exist

  if (mid*mid == x)
  { cout << "I won\n";
    return mid; }

  else if (mid*mid > x)
    return find_sqrt(a, mid-1, x);

  else
    return find_sqrt(mid+1, b, x); }

int my_sqrt(int N)
{ return find_sqrt(0, N+1, N); }

void main()
{ cout << "sqrt(6400) is " << my_sqrt(6400) << "\n";
  cout << "sqrt(6300) is around " << my_sqrt(6300) << "\n"; }