Question

1. 1- Complete/Modify the code given in quiz3.cpp to calculate the avg and the std deviation of the array a and write the output once to myquiz3outf.txt, and

   another time to a file to myquiz3outc.txt. (You must write one function for the mean(avg) and one function for the std.

#include<iostream>
#include<string>
#include<fstream>
#include<cstdlib> //new g++ is stricter - it rquires it for exit



using namespace std;


int max(int a[],int dsize){
    
    if (dsize>0){
        int max=a[0];
        for(int i=0;i<dsize;i++){
            if(a[i]>max){
                max = a[i];
            }
        }
        return max;
    }
    return -9999999;
}
int min(int a[],int dsize){
    
    if (dsize>0){
        int min=a[0];
        for(int i=0;i<dsize;i++){
            if(a[i]<min){
                min = a[i];
            }
        }
        return min;
    }
    return -9999999;
}

void printArray(int array[],int dsize){
    for(int i=0;i<dsize;i++){
        cout << array[i];
        if(i<dsize-1) //to avoid printing a space after the last one
            cout << " ";
    }
    cout << endl;
}
void fillArray(int array[],int &dsize, ifstream &fin){
    
    int i=0;
    while(!fin.eof()){
        fin >> array[i];
        i++;
    }
    dsize =i;
    
}

int main(){
    ifstream fin;
    ofstream fout;
    string ifilename="/home/ec2-user/environment/quizzes/numbers.txt";
    
    int const asize=100;
    int a[asize];
    int dsize=0;
    
    fin.open(ifilename.c_str()); //make sure you use the c_str the new g++ uses it
    if(!fin){ cout<< "Error opening input file"<<endl;exit(1);}
    fillArray(a,dsize,fin);
    printArray(a,dsize);
    cout <<"Min Value:" << min(a,dsize) << endl;
    cout <<"Max Value:" << max(a,dsize) << endl;
    
    return 0;
}

Answer 1

Please look at my code and in case of indentation issues check the screenshots.

--------------quiz3.cpp---------------

#include <iostream>
#include <string>
#include <fstream>
#include <cmath> //this header file is used for sqrt()
#include <cstdlib>   //new g++ is stricter - it rquires it for exit
using namespace std;

int max(int a[], int dsize)
{
   if (dsize > 0)
   {
       int max = a[0];
       for (int i = 0; i < dsize; i++)
       {
           if (a[i] > max){
               max = a[i];
           }
       }
       return max;
   }
   return -9999999;
}

int min(int a[], int dsize)
{
   if (dsize > 0)
   {
       int min = a[0];
       for (int i = 0; i < dsize; i++)
       {
           if (a[i] < min){
               min = a[i];
           }
       }
       return min;
   }
   return -9999999;
}

void printArray(int array[], int dsize)
{
   for (int i = 0; i < dsize; i++){
       cout << array[i];
       if (i < dsize - 1)   //to avoid printing a space after the last one
           cout << " ";
   }
   cout << endl;
}

void fillArray(int array[], int &dsize, ifstream &fin)
{
   int i = 0;
   while (!fin.eof()){
       fin >> array[i];
       i++;
   }
   dsize = i;
}

///////////////Updated code here/////////////////////////

//this function calculates mean of the array elements
double meanAvg(int array[], int arraySize)
{
   double sum = 0;           //initialize sum to 0
   for (int i = 0; i < arraySize; i++)
       sum = sum + array[i];         //calculate sum of all elements
   double mean = sum/arraySize;   //get the mean by dividing sum by arraySize
   return mean;                   //returns mean
}

//this function calculates standard deviation of arrayc elements
double std_deviation(int array[], int arraySize)
{
   double mean = meanAvg(array, arraySize);   //get the mean of array

   //Variance = ∑(array[i] – mean)2 / n
   double squareDiff = 0;      

   //get sum of squared differences from mean
   for (int i = 0; i < arraySize; i++)
       squareDiff = squareDiff + (array[i] - mean)*(array[i] - mean);

   double variance = squareDiff/arraySize; //calculate variance
   double std = sqrt(variance);   //standard deviation = sqrt of variance
   return std;                       //returns standard deviation
}

int main()
{
   ifstream fin;
   ofstream fout;
   //string ifilename = "/home/ec2-user/environment/bte320/numbers.txt";
   string ifilename = "numbers.txt"; //You can comment this line and use the above line

   int   const asize = 100;
   int a[asize];
   int dsize = 0;

   fin.open(ifilename.c_str());   //make sure you use the c_str the new g++ uses it
   if (!fin)
   {
       cout << "Error opening input file" << endl;
       exit(1);
   }
   fillArray(a, dsize, fin);
   printArray(a, dsize);
   cout << "Min Value:" << min(a, dsize) << endl;
   cout << "Max Value:" << max(a, dsize) << endl;

   //Updated code from here------------
   cout << "Mean :" << meanAvg(a, dsize) << endl;  
   cout << "Standard deviation :" << std_deviation(a, dsize) << endl;

   ofstream outfile1("myquiz3outf.txt");   //open output files for writing
   ofstream outfile2("myquiz3outc.txt");

   outfile1 << "Min Value:" << min(a, dsize) << endl;   //write output to files
   outfile1 << "Max Value:" << max(a, dsize) << endl;
   outfile1 << "Mean :" << meanAvg(a, dsize) << endl;
   outfile1 << "Standard deviation :" << std_deviation(a, dsize) << endl;

   outfile2 << "Min Value:" << min(a, dsize) << endl;
   outfile2 << "Max Value:" << max(a, dsize) << endl;
   outfile2 << "Mean :" << meanAvg(a, dsize) << endl;
   outfile2 << "Standard deviation :" << std_deviation(a, dsize) << endl;

   return 0;
}

----------Screenshots-----------------

----------Input--------------

----------Output--------------

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