随机但可预测的数字生成器？ [C ]

看看 random number generator used by VB6的C实现.它非常适合游戏,因为它产生相当可信的随机序列,但使用种子,同一种子总是生成相同的序列.因此,在游戏数据文件中,您可以保存一组种子值,这些种子值将为您提供可以轻松复制的已知(但随机查看)序列.

这是一个返回范围内值的实现：

typedef int Int32;
typedef unsigned int UInt32;

class CRnd
{
    private:
        static const UInt32 INITIAL_VALUE = 0x50000;
        static const UInt32 INCREMENT = 0xC39EC3;
        static const UInt32 MULTIPLIER = 0x43FD43FD;

    private:
        UInt32 m_nRnd;

    public:
        CRnd () { m_nRnd = INITIAL_VALUE; };
        CRnd ( IN UInt32 nSeed ) { m_nRnd = nSeed; };
        virtual ~CRnd () {};

        Int32 Get ( IN Int32 nFrom,IN Int32 nTo )
        {
            if ( nTo < nFrom ) // nFrom should be less than nTo
            {
                Int32 nTmp = nTo;

                nTo = nFrom;
                nFrom = nTmp;
            }
            else if ( nTo == nFrom )
            {
                return ( nTo );
            }

            m_nRnd = ( m_nRnd * MULTIPLIER + INCREMENT ) & 0xFFFFFF;

            float fTmp = (float) m_nRnd / (float) 16777216.0;

            return ( (Int32) ( ( fTmp * ( nTo - nFrom + 1 ) ) + nFrom ) );
        };

        void SetSeed ( IN UInt32 nSeed ) { m_nRnd = nSeed; };
        UInt32 GetSeed () { return ( m_nRnd ); };
};