Question

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.

side note: ***for the string ifilename, the folder name that the fils are under is "bte320" and the "numbers.txt" that it is referencing is pasted below***

CODE:

#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/bte320/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;
}

ARRAY FILE (numbers.txt):

55
9870
33
28
44
77
8756
312
2
78

Answer 1

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

---------main.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/////////////////////////

//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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Thankyou