C++의 vector로부터 표준편차와 평균 구하기

C++의 vector에 저장된 값으로 부터 표준편차와 평균을 구하는 예제 코드입니다. 

 

 

2021. 10. 10  - 최초작성

 

#include <iostream>
#include <numeric>
#include <vector>
#include <math.h>
#include <algorithm>


using namespace std;


int main()
{
    vector<int> v = {1, 2, 3, 4, 5};

    double sum = std::accumulate(v.begin(), v.end(), 0.0);
    double mean = sum / v.size();

    std::vector<double> diff(v.size());
    std::transform(v.begin(), v.end(), diff.begin(), [mean](double x) { return x - mean; });
    double sq_sum = std::inner_product(diff.begin(), diff.end(), diff.begin(), 0.0);
    double stdev = std::sqrt(sq_sum / v.size());

    cout << "mean : " << mean << endl;
    cout << "stdev : " << stdev << endl;
}

 

실행 결과

mean : 3 stdev : 1.41421

 

출처 - https://stackoverflow.com/questions/7616511/calculate-mean-and-standard-deviation-from-a-vector-of-samples-in-c-using-boos

Calculate mean and standard deviation from a vector of samples in C++ using Boost