Write a program to read a list of exam scores given as integer percentages in the range 0 to 100. Display the total number of grades and the number of grades in each letter-grade category as follows: 90 to 100 is a A, 80 to 89 is a B, 70 to 79 is a C, 60 to 69 is a D, and 0 to 59 is an F. Use a negative score as a sentinel value to indicate the end of the input. (The negative value is used only to end the loop, so do not use it in the calculations.) For example, if the input is 98 87 86 85 85 78 73 72 72 72 70 66 63 50 -1 the output would be Total number of grades = 14 Number of A's = 1 Number of B's = 4 Number of C's = 6 Number of D's = 2 Number of F's = 1

I am writing a C++ program.

#include <iostream> //to use input output functions

using namespace std; //to identify objects such as cout, cin

int main(){//start of main() function body

/*integer type variables A B C D and F are used to store the number of grades in each category example 90 to 100 is a A so its stored in A variable*/

               int A = 0;

 int B = 0;

 int C = 0;

 int D = 0;

 int F = 0;

 int total_grades=0; //counts and stores the total number of grades

//prompts user to enter exam scores

cout<<"Enter exam scores as integer percentages from 0 to 100:\n";

 int exam_score; // stores exam scores entered by user

 cin>>exam_score; // reads exam scores input by user

/* while loop continues to count the total number of grades and grades in each letter grade category until the user enters a negative value to end loop */

 while(exam_score>0){ //iterates till value of score is greater than 0

//increments the value of total_grades by 1 every time user enters the grade

                              total_grades++;

/*if condition checks if the value of exam_score is in the specified range of each grade category and increments that grade variable accordingly*/

   if(exam_score>=90 && exam_score<=100)

   A++;

   else if(exam_score>=80 && exam_score<=89)

   B++;

   else if(exam_score>=70 && exam_score<=79)

   C++;

   else if(exam_score>=60 && exam_score<=69)

   D++;

   else if(exam_score>=0 && exam_score<=59)

   F++;

   cin>>exam_score;  }

/*when the loop ends the total number of grades and number of grades in each letter grade category is displayed*/

 cout<<"Total number of grades :"<<total_grades<<endl;

 cout<<"Number of A's: "<<A<<endl;

 cout<<"Number of B's: "<<B<<endl;

 cout<<"Number of C's: "<<C<<endl;

 cout<<"Number of D's: "<<D<<endl;

 cout<<"Number of F's: "<<F<<endl;

}

Explanation:

The program first prompts the user to enter the exam scores. The while loop begins which keeps counting the number of grades and stores it in total_grades variable. Then the if condition checks for each letter grade category and counts the grades in each letter grade accordingly. For example if the exam score entered by user is between 90 to 100 then this means that the letter grade category is A , so the value of A is incremented by 1. The loop continues to execute until the user enters a negative value. For example if the user enters -1, then the loop breaks. At the end the total number of grades and the number of grades in each letter grade category which are computed in the while loop are displayed as output.

i'm pretty sure data is stored in a form