C + +: Random number of normal distribution (norm distribution) detailed

The normal distribution (norm distribution), as an important distributing law, has a wide range of uses;

Note that the normal distribution contains two parameters, mean (mean) and standard deviation (standard deviation);

Random library (#include <random>), which contains normal distribution objects, NORM_DISTRIBUTION<>, can be used to generate normal distribution;

The code is as follows:

#include <iostream>  
#include <vector>  
#include <string>  
#include <random>  
#include <algorithm>  
#include <cmath>  
      
      
using namespace std;  
      
      
int main ()  
{  
    std::d efault_random_engine E;//engine  
    std::normal_distribution<double> N (4, 1.5);//mean value, Variance  
    std::vector<unsigned> Vals (9);  
    For (std::size_t i=0 i!= ++i) {  
        unsigned v = std::lround (n (e));//rounding-nearest integer  
        if (v < vals.size ())  
            + + VALS[V];  
    }  
    For (std::size_t j=0 J!= vals.size (); ++j)  
        std::cout << J << ":" << Vals[j] << Std::strin G (Vals[j], ' * ') << Std::endl;  
      
    int sum = std::accumulate (Vals.begin (), Vals.end (), 0);  
    Std::cout << "sum =" << sum << std::endl;  
    return 0;  
}

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Output:

0:3***  
1:8********  
2:20********************  
3:38**************************************  
4:58***  
5:42******************************************  
6:23***********************  
7:7*******  
8:1*  
sum = 200

Author: csdn Blog spike_king