Convertion of grey code and binary 格雷码和二进制数之间的转换

以下转换代码摘自维基百科 Wikipedia：

/*
        The purpose of this function is to convert an unsigned
        binary number to reflected binary Gray code.

        The operator >> is shift right. The operator ^ is exclusive or.
*/
unsigned int binaryToGray(unsigned int num)
{
        return (num >> ) ^ num;
}

/*
        The purpose of this function is to convert a reflected binary
        Gray code number to a binary number.
*/
unsigned int grayToBinary(unsigned int num)
{
    unsigned int mask;
    for (mask = num >> ; mask != ; mask = mask >> )
    {
        num = num ^ mask;
    }
    return num;
}