C++随机数生成

#include <QCoreApplication>
#include<QDebug>
#include<QTimer>
#include<random>
#include<iostream>
#include<vector>

using namespace std;


vector<unsigned> good_randVec()
{
    //they are must be set Static because it design for generate same set when doing debug
    static default_random_engine e;
    static uniform_int_distribution<unsigned> u(0,9);
    vector<unsigned> ret;
    for(size_t i = 0;i<100;++i)
        ret.push_back(u(e));

    return ret;

}






int main(int argc, char *argv[])
{
    QCoreApplication a(argc, argv);
    //return unsigned int
    default_random_engine e;
    cout<<e.max()<<endl;
    cout<<e.min()<<endl;
    e.seed(2);
    for(size_t i = 0;i<10;i++)
    {
        cout<<e()<<endl;
    }


    //use int distribution
    cout<<"use int distribution class to set the range"<<endl;

    uniform_int_distribution<unsigned> u(0,9);

    default_random_engine e1;
    for(size_t i =0;i<10;i++)
    {
        cout<<u(e1)<<endl;

    }





    default_random_engine e4;
    normal_distribution<> n (4,1.5); //average = 4  distribution = 1.5
    vector<unsigned> vals(9);
    for(size_t i=0;i!= 300;i++)
    {
        unsigned v = lround(n(e4));
        if(v<vals.size())
            ++vals[v];


    }

    for(size_t j = 0;j<vals.size();++j)
    {
        cout<<j<<string(vals[j],'*')<<endl;

    }









    QTimer::singleShot( 0, &a, &QCoreApplication::quit );

    return a.exec();
}