随机数生成类。封装c++的rand函数，用于生成均匀、正态、伽马、贝塔、泊松、指数、几何等分布规律的随机数。
内含生成各分布的算法源码。各分布可通过ts测试。,A random number generator class. it Packages the rand function of C++,and is used to generate uniform, normal, gamma, beta, Poisson, exponential, geometric and other distribution of the random numbers. all The distributions can pass ts test.