import java.lang.Math.*;

public class numProbes
{
  /**
  *
  * Bret Curtis CPSC 321
  * Number of Probes Java Program
  *
  * Simple Log2(N)+1 program where N is the array size. 
  *
  **/
  public static void main( String[] args)
  {
    if (args.length == 0)
    {
      throw new IllegalArgumentException("Please pass a number as an argument.");        
    }
    else
    {
      int number = Integer.parseInt(args[0]);
    
      System.out.println("Array size of " + number + " can take up to " + manProbes(number) + " iterations ");
      System.out.println("to find an element using the  Binary Search algorithm.");
    }
  }
  
  /**
  * Compute maximum number of probes necessary to determine
  * if an item is in an array where the binary search
  * algorithm is being used.
  *
  *  @param n
  *    an integer
  *  @precondition
  *    n > 0 and n < 1,000,000
  *  @postcondition
  *    return the maximum number of probes as described above
  *  @throws java.lang.IllegalArgumentException
  *    indicates that n is less than or equal to 0
  *  @return
  *    return the maximum number of probes as described above
  **/
  public static int manProbes( int n )
  {
  double number = 0;

    if ( ( n > 0 ) && ( n < 1000000 ) )
    {
      number = Math.floor((Math.log(n)/Math.log(2))+1);
      return (int)number;
    }
    else
    {
      throw new IllegalArgumentException("Argument " + n + " is < 1 or > 1,000,000, please try again.");
    }
  }
}