Write a program that takes a list of final scores for a class and determines: 1)

Question

Write a program that takes a list of final scores for a class and determines: 1) the mean (Greek letter mu), 2) the standard deviation (Greek letter sigma), and 3) the number of grades in each category (A, A-, B+, B-, C+, C, C-, D+, D, and F).

Prompt the user for the name of a file containing the final scores, up to 100 scores.

Determine the maximum score, the minimum score, the range of scores (maximum minimum) and a table with column headings:

Grade:

Number of scores:

using the following scoring (where m is the mean, s is the standard deviation, and x is an individual score):

Place the output in a file, in an orderly format, and inform the user of the name of the file before exiting.

Remember to add comments in your program.

Explanation / Answer

#include<iostream>
#include<fstream>
#include<cmath>
using namespace std;
int main()
{
   ifstream file; // opening file to read
   string FileName;
int a[100],n=0;
cout << "Please enter the input filename --> "; // reading file name from user
cin >> FileName;
file.open(FileName.c_str());

while(!file.eof()) // reading from file data to array a;
{
file>>a[n];
n++;
}
  
int min=a[0],max=a[0],range;
   double m,s,sum=0;
for(int i=0;i<n;i++) // finding max, min, range, mean
{
        if(a[i]<min)
        min=a[i];
        if(a[i]>max)
        max=a[i];
        sum=sum+a[i];
}
m=sum/n;
m+=1;
range=max-min;
sum=0;
for(int i=0;i<n-1;i++) // finding the standard deviation
{
   sum=sum+((a[i]-m)*(a[i]-m));
}
sum=sum/n+1;
s=sqrt(sum);
  
double grade[10];
       int j=0,count[11]={0};
for(double i=4;i>=-5;i--) // calculating the grade, which is given as the formula
{
   grade[j]=m+(i/3)*s;
  
   j++;
}
  
for(int i=0;i<n;i++) // counting the number of scores of every grade
{
   if(grade[0]<=a[i])
   count[0]++;
   if(grade[1]<=a[i]&&a[i]<grade[0])
   count[1]++;
   if(grade[2]<=a[i]&&a[i]<grade[1])
   count[2]++;
   if(grade[3]<=a[i]&&a[i]<grade[2])
   count[3]++;
   if(grade[4]<=a[i]&&a[i]<grade[3])
   count[4]++;
           if(grade[5]<=a[i]&&a[i]<grade[4])
   count[5]++;
           if(grade[6]<=a[i]&&a[i]<grade[5])
   count[6]++;
           if(grade[7]<=a[i]&&a[i]<grade[6])
   count[7]++;
           if(grade[8]<=a[i]&&a[i]<grade[7])
   count[8]++;
   if(grade[9]<=a[i]&&a[i]<grade[8])
   count[9]++;
   if(grade[10]<=a[i]&&a[i]<grade[9])
   count[10]++;
   if(a[i]<grade[10])
   count[11]++;
  
}
  
ofstream out; // opening file for write
out.open("output.txt");
cout<<"Output in the file 'output.txt' ";
out<<" mean: "<<m<<" standard deviation: "<<s;
j=65; //ascii value of j is A
out<<" maximum: "<<max<<" minimum: "<<min<<" range of scores: "<<range;
out<<" Grade "<<"Number of Scores ";
   out<<" A "<<count[0];
   out<<" A- "<<count[1];
   out<<" B+ "<<count[2];
   out<<" B "<<count[3];
   out<<" B- "<<count[4];
   out<<" C+ "<<count[5];
   out<<" C "<<count[6];
   out<<" C- "<<count[7];
   out<<" D+ "<<count[8];
   out<<" D "<<count[9];
   out<<" F "<<count[10];
       return 0;
}

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