GetMean is a math code snippet to calculate the mean value of a container.


#include <numeric>

#include <vector>



//From htpp://www.richelbilderbeek.nl/CppGetMean.htm

double GetMean(const std::vector<double>& v)

{

  return std::accumulate(v.begin(),v.end(),0.0) / static_cast<double>(v.size());

}

GetMean test


#include <cstdlib>



//From htpp://www.richelbilderbeek.nl/CppGetRandomUniform.htm

double GetRandomUniform()

{

  return static_cast<double>(std::rand())/static_cast<double>(RAND_MAX);

}



#include <numeric>

#include <vector>



//From htpp://www.richelbilderbeek.nl/CppGetMean.htm

double GetMean(const std::vector<double>& v)

{

  return std::accumulate(v.begin(),v.end(),0.0) / static_cast<double>(v.size());

}



#include <iostream>



//From htpp://www.richelbilderbeek.nl/CppGetMean.htm

int main()

{

  std::vector<double> v;



  int max = 1;

  while (max != 33554432)

  {

    for (int i=0; i!=max; ++i)

    {

      v.push_back(GetRandomUniform());

    }

    std::cout << max << ": " << GetMean(v) << std::endl;



    max*=2;

  }

}

Screen output:


Starting /MyFolder/MyProject...

1: 0.840188

2: 0.672557

4: 0.608647

8: 0.586479

16: 0.501351

32: 0.513881

64: 0.540336

128: 0.522455

256: 0.50905

512: 0.506968

1024: 0.501297

2048: 0.500375

4096: 0.499167

8192: 0.497042

16384: 0.498369

32768: 0.499101

65536: 0.499806

131072: 0.500009

262144: 0.50013

524288: 0.499998

1048576: 0.499937

2097152: 0.500009

4194304: 0.50003

8388608: 0.500028

16777216: 0.500002

/MyFolder/MyProject exited with code 0

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(C++) GetMean

GetMean test