#include <iostream>

using std::cout;
using std::endl;
using std::ostream;

int bin_test(int ar[], int arsize, int desired_value);
int bin_recurs(int ar[], int desired_value, int lo, int hi);

int main() 

{

  int ar[10] = {10, 20, 30, 40, 50, 60, 70};
  int arsize = 7;
  int result;

  bin_test(ar, 7, 30);
  bin_test(ar, 7, 32);
  bin_test(ar, 7, 10);
  bin_test(ar, 7, 70);
  bin_test(ar, 7, 8);
  bin_test(ar, 7, 72);

  return 0;
}

// ***********************************

int bin_test(int ar[], int arsize, int desired_value)
{
  int result;
  cout << "searching for " << desired_value << endl;

  result = bin_recurs(ar, desired_value, 0, arsize - 1);

  if (result == -1)
    cout << desired_value << " is not in array" << endl << endl;
  else
    cout << desired_value << " is at slot " << result << endl << endl;
  
  return 0;
}

int bin_recurs(int ar[], int desired_value, int lo, int hi)
{
  int mid;

  cout << "entering bin_recurs from " << lo << " to " << hi << endl;

  if (hi < lo)
    return(-1);

  mid = (lo + hi)/2;

  if (ar[mid] == desired_value)
    return(mid);

  if (desired_value < ar[mid])
    return bin_recurs(ar, desired_value, lo, mid-1);
  else
    return bin_recurs(ar, desired_value, mid+1, hi);
}