// Random48.h - CSC 601 - Fall 2002 - Kirby
//
// A common 48-bit random number generator.
// See http://www.opengroup.org/onlinepubs/007908799/xsh/drand48.html. 
//
// Example usage:
//
//  Random48 rand( 1960 ) ;
//  int i= rand.next() % n ;     // random int 0...n-1
//

#include <ctime>
#include <cassert>

class Random48
{
public:
    Random48( unsigned int seed ) 
        : _hi( seed ), _lo( 0x330E ) {}

    int next()  
    {
      _hi = (_hi * 0xDEECE66D) + (_lo * 0x5DEEC) ;
      _lo = _lo * 0xE66D + 0xB ;
      _hi = _hi + (_lo >> 16) ;
      _lo = _lo & 0xFFFF ;
      return (_hi >> 1) ;
    }

private:
    unsigned int _hi, _lo ;
} ;