kbruch/src/primenumber.h

   1 /***************************************************************************
   2                           primenumber.h  -  class primenumber
   3                              -------------------
   4     begin                : Tue Nov 27 16:40:42 CET 2001
   5     copyright            : (C) 2001 by Sebastian Stein
   6     email                : seb.kde@hpfsc.de
   7  ***************************************************************************/
   8
   9 /***************************************************************************
  10  *                                                                         *
  11  *   This program is free software; you can redistribute it and/or modify  *
  12  *   it under the terms of the GNU General Public License as published by  *
  13  *   the Free Software Foundation; either version 2 of the License, or     *
  14  *   (at your option) any later version.                                   *
  15  *                                                                         *
  16  ***************************************************************************/
  17
  18 #ifndef PRIMZAHL_H
  19 #define PRIMZAHL_H
  20
  21 #include <qvaluevector.h>
  22
  23 typedef QValueVector<uint> UnsignedIntArray;
  24
  25 /** Class to handle prime numbers.
  26  *  The prime numbers are stored in a static vector, so that different instances
  27  *  can use them. Each time a higher prime number is needed, the new found prime
  28  *  number is stored in the vector. To check if a given number is a prime number
  29  *  this vector is scanned and if needed new prime numbers are generated. This
  30  *  algorithm should reduce calculation time and speed up every program using
  31  *  this prime number class.
  32  *  \author Sebastian Stein */
  33 class primenumber
  34 {
  35 public:
  36         /** constructor */
  37         primenumber();
  38
  39         /** destructor */
  40         ~primenumber();
  41
  42         /** returns wether the given number is a prime number */
  43         short isPrimeNumber(uint number);
  44
  45         /** returns the next prime number */
  46         unsigned int get_next();
  47
  48         /** returns the first prime number */
  49         unsigned int get_first() const;
  50
  51         /** return the last known prime number */
  52         unsigned int get_last() const;
  53
  54         /** returns the current prime number */
  55         unsigned int get_current() const;
  56
  57         /** moves the internal pointer to the first prime number */
  58         void move_first();
  59
  60         /** moves the internal pointer to the last prime number */
  61         void move_last();
  62
  63         /** moves the internal pointer to the next prime number */
  64         void move_forward();
  65
  66         /** moves the internal pointer to the previous prime number */
  67         void move_back();
  68
  69         /** Displays all known prime numbers, mainly used for debugging. */
  70         void display_all();
  71 private:
  72         /** a vector storing all known prime numbers, access for all objects;
  73          * we are using the vector<T> template; so we do not have to think
  74          * about dynamic mem manipulation */
  75         static UnsignedIntArray prim_vector;
  76
  77         /** current selected prime number */
  78         UnsignedIntArray::iterator current_pos;
  79
  80         /** finds next prime number and adds it to the vector */
  81         void find_next();
  82 };
  83 #endif