c++随机数引擎

/**
 * 作者: cwl
 * 描述: c++ 随机数引擎生成随机数
 * */
#include <bits/stdc++.h>

using namespace std;

template <typename T>
void printVector(std::vector<T> &vec, int index = 0) {
    cout << "[" << index << "] ";
    for(auto &iter: vec) {
        cout << "" << iter << " ";
    }
    cout << endl;
}

int main()
{

    //随机数普遍是通过线性同余运算产生的为伪随机，之前我们用rand() % mod
    //这里我们尝试随机数引擎

    auto randomVectorUnsigned = [](int count) -> vector<unsigned int> {
        int random_seed = time(0);
        //可以用下面两种方式设置seed
        default_random_engine e(random_seed);
        e.seed(random_seed);
        //随机数
        uniform_int_distribution<unsigned int>u(0, 100);
        vector<unsigned int>vec;
        for(auto i = 1; i <= count; ++i) {
            vec.push_back(u(e));
        }
        return vec;
    };

    vector<unsigned int> test_int = randomVectorUnsigned(10);
    printVector(test_int, 1);

    auto randomVectorDouble = [](int count) -> vector<double> {
        int random_seed = time(0);
        //可以用下面两种方式设置seed
        default_random_engine e(random_seed);
        e.seed(random_seed);
        //随机数
        uniform_real_distribution<double>u(0, 10);
        vector<double>vec;
        for(auto i = 1; i <= count; ++i) {
            vec.push_back(u(e));
        }
        return vec;
    };
    vector<double> test_double = randomVectorDouble(10);
    printVector(test_double, 2);

    //生成非均匀的随机数

    auto randomVector = [](int count) -> vector<double> {
        int random_seed = time(0);
        //可以用下面两种方式设置seed
        default_random_engine e(random_seed);
        e.seed(random_seed);
        //随机数
        normal_distribution<> n(4, 1.5); //均值4，标准差1.5；
        vector<double>vec;
        for(auto i = 1; i <= count; ++i) {
            vec.push_back(n(e));
        }
        return vec;
    };
    vector<double> test = randomVector(10);
    printVector(test);


    return 0;
}