Question

In C++

This program will read a group of positive numbers from three files ( not all necessarily the same size), and then calculate the average and median values for each file. Each file should have at least 10 scores. The program will then print all the scores in the order that they were input, showing each number and what percentage it is above or below the average for each file. Note: Finding the average doesn’t require an array. Finding the median and the percentages does require an array.

• The user should be prompted for the three file names which you should store in sring variables for file processing.
• The program will read values until the user encounters an EOF for that file to quit.
• The program must provide an error message for zero or other negative numbers.
• Do not presume that all the numbers will be integers..
• The program must provide reasonable prompts and error messages to the users.
• The program’s output must be properly labelled.
• The program must handle the case of an empty array properly by producing a reasonable error message. It must not attempt to do any calculations on the empty array.
• The program’s output does not need to be lined up perfectly.
• You must display the deviations from the average as positive numbers with some wording (e.g., 50.253% below and 25.22% above) rather than as a simple number (e.g., -50.253% and 25.22%) for each file with a heading for each file corresponding to the lable as given below..
• Finally It should have embedded in each file a lable for that file ( name of the scores) such as class A, class B , class C etc.
• Print out the lable for the file and the average for the file with the highest average and its value. Do the same for the file with the highest median, and f inally the file with the highest average of the percentage below the average for that file and its value.

Finding the Median

To find the median of a group of n numbers, sort them into order. If n is odd, the median is the middle entry. In an array named @data with elements starting at index zero, this will be element $data[(n-1)/2]. (Of course, you will have to put a scalar variable in place of n)

If n is even, the median is the average of the numbers “surrounding” the middle. For an array named @data with elements starting at index zero, this is ($data[(n/2)]+$data[(n/2)-1])/2.

Here is sample output from three separate runs of the program. User input in bold and italics.

Scores Report

Enter fie name for first file : class_A.txt

Enter fie name for first file : class_B.txt

Enter fie name for first file : class _C.txt

For class A
 
The average is 8
The median value is 6
Value   % above/below average
4       50% below
6       25% below
14      75% above

For class B

The average is 9
The median value is 10
Value   % above/below average
3       50% below
6       25% below
12      75% above

For class C

The average is 7
The median value is 6
Value   % above/below average
4       50% below
8       25% below
9       75% above

File A had the highest average of 35.5 
File B had the highest median of 34
File C had the highest average  percent of the scores below the average with a value of 47.25.
 

In this example, the percentages all happened to come out to be integers. For an arbitrary set of numbers, this won’t be the case. Do not truncate your results to integers use two decima places for values that our output.

Sorting an Array Numerically

When you sort an array, the default is to sort in alphabetical (ASCII/Unicode) order. This isn’t what you want for an array containing numbers. Otherwise, the number "47" (as a string) will sort before the number "5" (as a string).

Answer 1

olution(s):

Code :

// averageAndMedian.cpp : Defines the entry point for the console application.
//

#include<iostream>
#include<string>
#include <fstream>
#include <stdlib.h>

using namespace std;

//reading class from filename
double* readClass(string fileName,double& avg,double& countArray){
//defining local variables
   double *arrayName = NULL;
   double temp=0,sum=0;
   int count=0;
   string line;
   size_t sz = 0;
   ifstream f (fileName);
   //opening file
   if (!f.is_open())
   {
       //printing error if file not found
       perror("Error while opening file");
   }else{
   while(getline(f, line)) {
       //converting string to double  
       temp=stod(line);
       //checking if value is less than equal to zero
           if(temp<=0){
               //printing message and ignoring file
           cout<<"Value cannot be :"<<temp<<" in:"<<fileName<<endl;
           }else{
               //adding sum and in this loop only counting valid entries
           sum+=temp;
           count++;
           }
           //cout<<stod(line)<<endl;
       }
   //closing file
   f.close();
   ifstream f (fileName);
   int index=0;
   if(count>0)
   arrayName = new double [count]; //creating dynamic array

   //adding file data to new array
   while(getline(f, line)) {
           temp=stod(line);
           if(temp>0){  
               arrayName[index]=temp;
               index++;
           }
       }
   }
   //checking if file has some valid data
   if(sum!=0)
   {
       avg=sum/count;
       countArray=count;
   }else{//returning default
   avg=0;
   countArray=0;
   }
  
   return arrayName;
}

//function to swap two numbers
void swap(double *p,double *q) {
int t;

t=*p;
*p=*q;
*q=t;
}

//sort function
void sort(double a[],int n) {
int i,j,temp;

for(i = 0;i < n-1;i++) {
for(j = 0;j < n-i-1;j++) {
if(a[j] > a[j+1])
swap(&a[j],&a[j+1]);
}
}
}
//median function
double getMedian(double arrayName[],int n){
   sort(arrayName,n);
   if (n % 2 != 0)
return (double)arrayName[n/2];
  
return (double)(arrayName[(n-1)/2] + arrayName[n/2])/2.0;
}

//printing results and getting average below value
void printResults(double average,int count,double *className,double &averageBelow){
   int sumBelow=0;
   if(count>0)
   {
   cout<<"The Average Value Is : "<<average<<endl;
   cout<<"The Median Value Is : "<<getMedian(className,count)<<endl;
   cout<<"Value % above/below average ";
   for(int i=0;i<count;i++)
   {
       double percentBelowAbove=0;
       percentBelowAbove=((className[i]-average)/average) * 100;
       if(percentBelowAbove<0)
       {
           cout<<className[i]<<" "<<percentBelowAbove*-1<<"% below ";
           sumBelow-=percentBelowAbove;
       }else if(percentBelowAbove>0)
       {
           cout<<className[i]<<" "<<percentBelowAbove<<"% above ";
       }else{
           cout<<className[i]<<" % is same ";
       }
   }
   averageBelow=sumBelow/count;
   }else{
   cout<<"No valid data found";
   averageBelow=100;
   }
  
}
//Main class to call functions
void main()
{
   double *classA = NULL;
   double *classB = NULL;
   double *classC = NULL;
   double classAAvergage,countA,classBAvergage,countB,classCAvergage,countC;
   double classAAvergageBelow,classBAvergageBelow,classCAvergageBelow;
   double classAMedian,classBMedian,classCMedian;
   string classAFileName,classCFileName,classBFileName;

   cout<<"Enter Name for first file: ";
   //classAFileName="c:\users\faraz\desktop\a.txt";
   //classBFileName="c:\users\faraz\desktop\b.txt";
   //classCFileName="c:\users\faraz\desktop\c.txt";
   cin>>classAFileName;
   cout<<"Enter Name for second file: ";
   cin>>classBFileName;
   cout<<"Enter Name for third file: ";
   cin>>classCFileName;

   classA=readClass(classAFileName,classAAvergage,countA);
   classB=readClass(classBFileName,classBAvergage,countB);
   classC=readClass(classCFileName,classCAvergage,countC);
  
   cout<<" For class A ";
   printResults(classAAvergage,countA,classA,classAAvergageBelow);
   cout<<" For class B ";
   printResults(classBAvergage,countB,classB,classBAvergageBelow);
   cout<<" For class C ";
   printResults(classCAvergage,countC,classC,classCAvergageBelow);
   classAMedian=getMedian(classA,countA);
   classBMedian=getMedian(classB,countB);
   classCMedian=getMedian(classC,countC);
  
   if(classAAvergage>classBAvergage && classAAvergage>classCAvergage)
   {
       cout<<"File A had the highest average of "<<classAAvergage<<endl;
   }
   else if(classBAvergage>classAAvergage && classBAvergage>classCAvergage)
   {
       cout<<"File B had the highest average of "<<classBAvergage<<endl;
   }
   else if(classCAvergage>=classAAvergage && classCAvergage>classBAvergage)
   {
       cout<<"File C had the highest average of "<<classCAvergage<<endl;  
   }else
   {
   cout<<"All average are same having value of "<<classAAvergage<<endl;
   }

   if(classAMedian>classBMedian && classAMedian>classCMedian)
   {
       cout<<"File A had the highest median of "<<classAMedian<<endl;
   }
   else if(classBMedian>classAMedian && classBMedian>classCMedian)
   {
       cout<<"File B had the highest median of "<<classBMedian<<endl;
   }
   else if(classCMedian>=classAMedian && classCMedian>classBMedian)
   {
       cout<<"File C had the highest median of "<<classCMedian<<endl;  
   }else
   {
   cout<<"All median are same having value of "<<classAMedian<<endl;
   }

   if(classAAvergageBelow>classBAvergageBelow && classAAvergageBelow>classCAvergageBelow)
   {
       cout<<"File A had the highest average percent of the scores below the average with a value of "<<classAAvergageBelow<<endl;
   }
   else if(classBAvergageBelow>classAAvergageBelow && classBAvergageBelow>classCAvergageBelow)
   {
       cout<<"File B had the highest average percent of the scores below the average with a value of "<<classBAvergageBelow<<endl;
   }
   else if(classCAvergageBelow>=classAAvergageBelow && classCMedian>classBAvergageBelow)
   {
       cout<<"File C had the highest average percent of the scores below the average with a value of "<<classCAvergageBelow<<endl;  
   }else
   {
   cout<<"All median are same having value of "<<classAAvergageBelow<<endl;
   }  

   system("Pause");
}

output: