Question

use c++

/*
The following function receives the class marks for all student in a course and compute standard deviation. Standard deviation is the average of the sum of square of difference of a mark and the average of the marks. For example for marks={25, 16, 22}, then average=(25+16+22)/3=21. Then standard deviation = ((25-21)^2 + (16-21)^2+(22-21)^2)/3.
Implement the function bellow as described above. Then write a test console app to use the function for computing the standard deviation of a list of marks that user inputs as floats in the range of 0.f to 100.f. User signals end of the list by entering -1 as final mark. Make sure to verify user input marks are valid and in the range, before processing them.

*/

float ComputeMarksStandardDeviation(std::array<float> marks)
{
}

Answer 1

C++ PROGRAM:

#include<iostream>

#include<vector>

#include<math.h>

using namespace std;

/**The following function receives the class marks

* for all student in a course and compute standard deviation.

* function for computing the standard deviation of a list of

* marks that user inputs as floats in the range of 0.f to 100.f.*/

float ComputeMarksStandardDeviation(std::vector<float> marks){

    float sum = 0;

    float MarksStandardDeviation;

    // find the size of the vector

    int n = marks.size();

    // calculate the sum of all marks

    for(int i=0; i<n; i++){

        sum+=marks[i];

    }

    /**For example for marks={25, 16, 22}, then average=(25+16+22)/3=21. Then

     * standard deviation = ((25-21)^2 + (16-21)^2+(22-21)^2)/3.

     * calculate the average of marks*/

    float average = sum/n;

    // calculate the standard deviation

    for(int i=0; i<n; i++){

        MarksStandardDeviation += pow(marks[i] - average, 2);

    }

    // return the standard deviation

    return MarksStandardDeviation/n;

}

// main() function

int main()

{   

    float num;

    vector<float> marks;

    while(true){

        cout<<"Enter marks: ";

        cin>>num;

        // User signals end of the list by entering -1 as final mark.

        if(num==-1) break;

        // Make sure to verify user input marks are valid and in the range,

        // between 0-100f

        while(num<0 || num>100){

            cout<<"Out of range"<<endl;

            cout<<"Enter marks between 0-100: ";

            cin>>num;

        }

       // push_back into the vector marks

        marks.push_back(num);

    }

   // calling and print the standard Deviation

    // Standard deviation is the average of the sum

    // of square of difference of a mark and the average of the marks

    cout<<"Standard Deviation: "<<ComputeMarksStandardDeviation(marks);

    return 0;

}

OUTPUT:

NOTE: If you don't understand any step please let me know at once.