package username.functions;

/**
 * The log function for a variety of bases.
 *
 * @author Samuel A. Rebelsky
 * @version 1.0 of April 2006
 */
public class LogUIF
  implements UnaryIntegerFunction
{

// +--------+-----------------------------------------------
// | Fields |
// +--------+
  
   int base;

// +--------------+-----------------------------------------
// | Constructors |
// +--------------+

  /** Build a new log function that uses base _base. */
  public LogUIF(int _base)
  {
    this.base = _base;
  } // LogUIF(int)

// +------------------+-------------------------------------
// | Standard Methods |
// +------------------+

  public String toString() 
  {
    return "log_" + this.base + "(x)";
  }

// +----------------+---------------------------------------
// | Public Methods |
// +----------------+

  public int apply(int x)
  {
    // Math tells me that log_b(x) = ln(x)/ln(b)
    return (int) (Math.log(x) / Math.log(this.base));
  } // apply(int)

} // LogUIF