#include <random>
int RandomNum(const int& Lowerlimit, const int& UpperLimit)
{
    std::random_device rd;
    std::mt19937 gen(rd());
    std::uniform_int_distribution<> dis(Lowerlimit, UpperLimit);
    int num = dis(gen);
    return num;
}

使用模板实现浮点数：

std::uniform_real_distribution<double> dis(Lowerlimit, UpperLimit);