Question

Professor Dolittle has asked some computer science students to write a program that will help him calculate his final grades. Professor Dolittle gives two midterms and a final exam. Each of these is worth 100 points. In addition, he gives a number of homework assignments during the semester. Each homework assignment is worth 100 points.

At the end of the semester, Professor Dolittle wants to calculate the median score on the homework assignments for the semester. He believes that the median score is a good measure of the student's overall performance on the homework assignments. The median is found by putting the homework scores in order, and then taking the score that is at the midpoint of this list. If there are an odd number of assignments, the median is the score exactly in the middle of the list. If there are an even number of assignments, the median is the average of the two scores closest to the midpoint of the data.

Once the median score is known, professor Dolittle takes the sum of the exam scores and the median homework score and uses this value to compute a letter grade. Letter grades are assigned based on the following table:

Total Score	Letter Grade
381 - 400	A
361 - 380	A-
341 - 360	B+
321 - 340	B
301 - 320	B-
281 - 300	C+
261 -280	C
241 - 260	C-
221 - 240	D+
201 - 220	D
181 - 200	D-
180 and below	fail

Program Requirements

Your program should work as follows:

1. All user input should be tested to be sure that it is a valid integer value in the range 0 to 100.
2. It should ask the user to enter in the score for the first midterm. Then this value is read in and saved.
3. It should ask the user to enter in the score for the second midterm. Then this value is read in and saved.
4. It should ask the user to enter in the score for the final exam. Then this value is read in and saved.
5. The program then asks the user to enter in the scores for the homework assignments. Any number of scores can be entered in. You will test for a -1 entry to stop adding to the vector.
6. Store the homework scores in a vector.
7. Once all of the data has been entered, the program calls FindMedianScore() that you have written to find the median homework score.
8. The program then calls CalculateLetterGrade() that you have written to calculate and return the letter grade. The return grade is based upon the total of the three exams plus the median homework score (total points).
9. Finally, display the median homework score, the total point count, and the letter grade.

Below is the expected output:

Dr. DoLittle's Grading Program .....

Please enter in the score for the first exam: abc

Sorry, your input must be an integer. Please try again.
Please enter in the score for the first exam: 97

Please enter in the score for the second exam: 65

Please enter in the score for the final exam: 85

Enter the score for a homework assignment: abc

Sorry, your input must be an integer. Please try again.
Enter the score for a homework assignment: 200

Sorry, your input must be between 0 and 100. Please try again.
Enter the score for a homework assignment: 99

Enter the score for a homework assignment: 65

Enter the score for a homework assignment: 78

Enter the score for a homework assignment: 80

Enter the score for a homework assignment: -1

The median homework score was 79
The total points earned was 326
The letter calculated letter grade is B

Below is the test input:

As a reminder, you need to place all input at once into the input window in Zylabs. For the example above, the input is:

abc
97
65
85
abc
200
99
65
78
80
-1

Code copied:

#include<iostream>
#include<vector>
#include<string>
using namespace std;

double FindMedianScore(vector<int>& scores);
string CalculateLetterGrade(int totalScore);

int main()
{
   double firstExam = 0.0;
   double secondExam = 0.0;
   double finalExam = 0.0;
  
   vector<int> scores;
  
   cout << "Dr. DoLittle's Grading Program ....." << endl;
  
   while (true)
   {
       cout << "Please enter in the score for the first exam : ";
       cin >> firstExam;
      
       //is it not a number?
       if (cin.fail()) //(!cin)
      
       {
           cout << "Sorry, your input must be an integer. Please try again." << endl;
           cin.clear();
           cin.ignore(1024, '\n');
       }

       //is it not between 0 and 100?
      
       else if (firstExam < 0 || firstExam > 100)
               {
           cout << "Sorry, your input must be an integer. Please try again." << endl;}
       else
       {
           break;
       }
   }
   while (true)
   {
       cout << "Please enter in the score for the second exam : ";
       cin >> secondExam;
//is it not a number?
       if (cin.fail()) //(!cin)
      
       {
           cout << "Sorry, your input must be an integer. Please try again." << endl;
           cin.clear();
           cin.ignore(1024, '\n');
       }

       //is it not between 0 and 100?
       else if (secondExam < 0 || secondExam > 100)
       {
           cout << "Sorry, your input must be an integer. Please try again." << endl;
       }
       else
       {
           break;
       }
   }

   //added
   cout << endl;

   while (true)
   {
       cout << "Please enter in the score for the final exam : ";
       cin >> finalExam;
       //is it not a number?
       if (cin.fail()) //(!cin)
       {
           cout << "Sorry, your input must be an integer. Please try again." << endl;
           cin.clear();
           cin.ignore(1024, '\n');
       }
       //is it not between 0 and 100?
       else if (finalExam < 0 || finalExam > 100)
       {
           cout << "Sorry, your input must be an integer. Please try again." << endl;
       }
       else
       {
           break;
       }
   }
   int inputValue = 0;
   while (inputValue != -1)
   {
       while (true)
       {
           cout << "Enter the score for a homework assignment: ";
               cin >> inputValue;
//is it not a number?
               if (cin.fail()) //(!cin)
               {
                   cout << "Sorry, your input must be an integer. Please try again." << endl;
                   cin.clear();
                   cin.ignore(1024, '\n');
               }

               //is it not between 0 and 100?
               else if (inputValue < -1 || inputValue > 100)
               {
                   cout << "Sorry, your input must be an integer. Please try again." << endl;
               }
               else
               {
                   if (inputValue != -1)
                   {
                       scores.push_back(inputValue);
                   }
                   break;
               }
       }
   }
   double median = FindMedianScore(scores);
   double total = firstExam + secondExam + finalExam + median;
   string letterGrade = CalculateLetterGrade(total);
   cout << "The median homework score was " << median << endl;
   cout << "The total points earned was " << total << endl;
   cout << "The letter calculated letter grade is " << letterGrade << endl;
}
double FindMedianScore(vector<int>& scores)
{
   //sort vector
   //determine if its even or odd size
   //get medianreturn 0.0;
   }
string CalculateLetterGrade(int totalScore)
   {
   return string();
}

Answer 1

I have provided the code for your question.

You just have to edit the the two functions , CalculateLetterGrade() and  FindMedianScore(). Additionally, a sorting function is also used which is implemented as Selection Sort (you need to declare the function above main. " void sort(vector<int>& arr);"). You can use any sorting function . If you can use the library funtions, you need to add #include <algorithm> as a header, and just use "sort(scores.begin(),scores.end());" in FindMedianScore() for sorting.

If you don't know what Selection Sort is. :

For every number from beginning, it find the number smaller than this element in the remaining array until the end and swaps these two elements.

This process is repeated until end.

The required functions' Code:-

double FindMedianScore(vector<int>& scores)
{ int mid = scores.size()/2;
double median;
// sort(scores.begin(),scores.end()); // Un comment this line if you can
// use the inbuild- sort function. for this you need to add "#include<algorithm>" as header in line 1.
sort(scores);
if(scores.size()%2==0){ // if its even , then median is average if middle two elements
  
median= (float)((scores[mid]+scores[mid-1])/2.0);
}
else median=(float)(scores[mid]/1.0); // else median is the middle element
//sort vector
//determine if its even or odd size
//get medianreturn 0.0;
return median;
}
string CalculateLetterGrade(int totalScore)
{
// this is straight forawrd.
if(totalScore>380)
return "A";
if(totalScore>360)
return "A-";
if(totalScore>340)
return "B+";
if(totalScore>320)
return "B";
if(totalScore>300)
return "B-";
if(totalScore>280)
return "C+";
if(totalScore>260)
return "C";
if(totalScore>240)
return "C-";
if(totalScore>220)
return "D+";
if(totalScore>200)
return "D";
if(totalScore>180)
return "D-";
else return "fail";
// return string();
}
/*Selection Sort Algorithm to sort a given vector.
Add the following line above main .
void sort(vector<int>& arr);
*/
void sort(vector<int>& arr){

for(int i=0; i<arr.size(); i++)
{
for(int j=i+1; j<arr.size(); j++)
{
if(arr[i]>arr[j])
{
int temp=arr[i];
arr[i]=arr[j];
arr[j]=temp;
}
}
}
}

**Thank You. Please comment for any additional clarifications.**

COMPLETE CODE:

#include<iostream>
#include<vector>
#include<string>
// #include<algorithm>
using namespace std;

double FindMedianScore(vector<int>& scores);
string CalculateLetterGrade(int totalScore);
void sort(vector<int>& arr);

int main()
{
double firstExam = 0.0;
double secondExam = 0.0;
double finalExam = 0.0;
  
vector<int> scores;
  
cout << "Dr. DoLittle's Grading Program ....." << endl;
  
while (true)
{
cout << "Please enter in the score for the first exam : ";
cin >> firstExam;
  
//is it not a number?
if (cin.fail()) //(!cin)
  
{
cout << "Sorry, your input must be an integer. Please try again." << endl;
cin.clear();
cin.ignore(1024, '\n');
}

//is it not between 0 and 100?
  
else if (firstExam < 0 || firstExam > 100)
{
cout << "Sorry, your input must be an integer. Please try again." << endl;}
else
{
break;
}
}
while (true)
{
cout << "Please enter in the score for the second exam : ";
cin >> secondExam;
//is it not a number?
if (cin.fail()) //(!cin)
  
{
cout << "Sorry, your input must be an integer. Please try again." << endl;
cin.clear();
cin.ignore(1024, '\n');
}

//is it not between 0 and 100?
else if (secondExam < 0 || secondExam > 100)
{
cout << "Sorry, your input must be an integer. Please try again." << endl;
}
else
{
break;
}
}

//added
cout << endl;

while (true)
{
cout << "Please enter in the score for the final exam : ";
cin >> finalExam;
//is it not a number?
if (cin.fail()) //(!cin)
{
cout << "Sorry, your input must be an integer. Please try again." << endl;
cin.clear();
cin.ignore(1024, '\n');
}
//is it not between 0 and 100?
else if (finalExam < 0 || finalExam > 100)
{
cout << "Sorry, your input must be an integer. Please try again." << endl;
}
else
{
break;
}
}
int inputValue = 0;
while (inputValue != -1)
{
while (true)
{
cout << "Enter the score for a homework assignment: ";
cin >> inputValue;
//is it not a number?
if (cin.fail()) //(!cin)
{
cout << "Sorry, your input must be an integer. Please try again." << endl;
cin.clear();
cin.ignore(1024, '\n');
}

//is it not between 0 and 100?
else if (inputValue < -1 || inputValue > 100)
{
cout << "Sorry, your input must be an integer. Please try again." << endl;
}
else
{
if (inputValue != -1)
{
scores.push_back(inputValue);
}
break;
}
}
}
double median = FindMedianScore(scores);
double total = firstExam + secondExam + finalExam + median;
string letterGrade = CalculateLetterGrade(total);
cout << "The median homework score was " << median << endl;
cout << "The total points earned was " << total << endl;
cout << "The letter calculated letter grade is " << letterGrade << endl;
}
double FindMedianScore(vector<int>& scores)
{ int mid = scores.size()/2;
double median;
// sort(scores.begin(),scores.end()); // Un comment this line if you can
// use the inbuild- sort function. for this you need to add "#include<algorithm>" as header in line 1.
sort(scores);
if(scores.size()%2==0){ // if its even , then median is average if middle two elements
  
median= (float)((scores[mid]+scores[mid-1])/2.0);
}
else median=(float)(scores[mid]/1.0); // else median is the middle element
//sort vector
//determine if its even or odd size
//get medianreturn 0.0;
return median;
}
string CalculateLetterGrade(int totalScore)
{
// this is straight forawrd.
if(totalScore>380)
return "A";
if(totalScore>360)
return "A-";
if(totalScore>340)
return "B+";
if(totalScore>320)
return "B";
if(totalScore>300)
return "B-";
if(totalScore>280)
return "C+";
if(totalScore>260)
return "C";
if(totalScore>240)
return "C-";
if(totalScore>220)
return "D+";
if(totalScore>200)
return "D";
if(totalScore>180)
return "D-";
else return "fail";
// return string();
}
/*Selection Sort Algorithm to sort a given vector.
Add the following line above main .
void sort(vector<int>& arr);
*/
void sort(vector<int>& arr){

for(int i=0; i<arr.size(); i++)
{
for(int j=i+1; j<arr.size(); j++)
{
if(arr[i]>arr[j])
{
int temp=arr[i];
arr[i]=arr[j];
arr[j]=temp;
}
}
}
}