Question

design and implement a c++ function that accepts the path of a file, reads the values a set of numbers from the file and returns the mean and the standard deviation of the numbers in there

Answer 1

#include <iostream>
#include <fstream>
#include <vector>
#include <math.h>


using namespace std;


void readNumbers(string pathOfTheFile)
{
    fstream read(pathOfTheFile);
    if(read.is_open())
    {
        vector<double> numbers;
        double number;


        while(!read.eof())
        {
            read >> number;
            numbers.push_back(number);
        }


        double sum = 0;
        for(int i = 0; i < numbers.size(); i++)
            sum+=numbers[i];


        double mean = sum/numbers.size();
        cout << "Mean is " << mean << endl;


        double standardDeviation = 0;
        for(int i = 0; i < numbers.size(); i++)
        {
            standardDeviation+=pow(numbers[i]-mean,2)/numbers.size();
        }
        standardDeviation = pow(standardDeviation, 0.5);


        cout << "Standard deviation is " << standardDeviation << endl;
    }
    else
        cout << "File not found";


    read.close();
}
int main()
{
    cout << "Enter path: ";


    string pathOfTheFile;
    getline(cin, pathOfTheFile);


    readNumbers(pathOfTheFile);


    cout << endl;
    return 0;

}

Explanation : create a file, for example numbers.txt and fill with the following numbers : 3 4 5 1 6 8 10 2 7 (all in one row), save the file, then run a program