Question

Write a C++ program that will display the following menu and work accordingly. A menu that will display the following choices and uses functions to carry out the calculations: 1. Call a function named classInfo() to ask the user the number of students and exams in a course. 2. Call a function getGrade() that will get the information from classInfo() and asks the user to enter the grades for each student. 3. Call a function courseGrade() to display the average and the letter grade for each student. 4. Exit. Note: You are free to choose the format for the functions, i.e. input-output format. A: 90-100; B: 80-80; C: 70-79; D: 60-69; F: 0-59 Make sure: (i) Follow proper documentation procedure. (ii) Options 2 & 3 can be done only if option 1 was selected before. (iii) You are free to choose your function formats. (iv) Result should be displayed with two decimal place accuracy. (v) Include one sample run with error detection for three students in the class and two exams. (vi) Error detection and correction is needed.

Answer 1

Answer:

C++ Program:

#include <iostream>

using namespace std;

//Function that reads number of students and exams
void classInfo(int &students, int &exams)
{
//Reading number of students
cout << "\n\n Enter number of students: ";
cin >> students;

//Reading number if exams
cout << "\n\n Enter number of exams: ";
cin >> exams;
}

//Function that allocates memory and reads grades from user
int* getGrade(int *grades, int &students, int &exams)
{
int i, j;

//If number of students were nor read
if(students == 0)
{
//Get number of students and exams
classInfo(students, exams);
}

//Allocating memory
grades = new int*[students];

//Allocating memory for each student
for(i=0; i<students; i++)
{
grades[i] = new int[exams];
}

//Iterating over students
for(i=0; i<students; i++)
{
cout << "\n For, Student " << (i+1) << ": Enter " << exams << " scores: ";

//Iterating over exams
for(j=0; j<exams; j++)
{
//Reading and storing grade
cin >> grades[i][j];
}
}

return grades;
}

//Function that finds the grade based on average
char getGrade(double avg)
{
char grade=' ';

//90-100 -> A
if(avg >= 90 && avg <= 100)
{
grade = 'A';
}
//80-89 -> B
else if(avg >= 80 && avg < 90)
{
grade = 'B';
}
//70-79 -> C
else if(avg >= 70 && avg < 80)
{
grade = 'C';
}
//60-69 -> D
else if(avg >= 60 && avg < 70)
{
grade = 'D';
}
//0-59 -> F
else
{
grade = 'F';
}

return grade;
}

//Function that displays grades
void displayGrades(int **grades, int students, int exams)
{
int i, j;
double sum=0, avg;
char grade;

//Iterating over number of students
for(i=0; i<students; i++)
{
//Printing student number
cout << "\n Student " << (i+1) << ": ";

//Set to 0 in each iteration
sum = 0;

//Iterating over grades
for(j=0; j<exams; j++)
{
//Accumulating sum
sum = sum + grades[i][j];
}

//Calculating average
avg = sum / (double)exams;

//Finding grade based on average
grade = getGrade(avg);

//Printing average and its corresponding grade
cout << " Average: " << avg << " \t Grade: " << grade << " \n";
}
}

//Main function
int main()
{
int ch, i;
int students=0, exams=0;
int **grades;

//Iterate till user wants to quit
while(1)
{
//Displaying menu
cout << "\n\n\t 1 - Get Class Info \n\t 2 - Get Grade \n\t 3 - Display Course Grade \n\t 4 - Exit \n\n\t Your Choice: ";
cin >> ch;

//Calling appropriate functions
switch(ch)
{
case 1: classInfo(students, exams); break;

case 2: grades = getGrade(grades, students, exams); break;

case 3: displayGrades(grades, students, exams); break;

case 4: exit(0);

default: cout << "\n\n Error!!! Invalid choice... \n";
}
}

//Deallocating memory
for(i=0; i<students; i++)
{
delete grades[i];
}

delete[] grades;

cout << "\n\n";
return 0;
}

sample output:

Answer 2

Below is a C++ program that implements the menu with the specified functions for calculating course grades based on user input. The program includes error detection and correction for the number of students and exams entered by the user.

cppCopy code#include <iostream>#include <iomanip>using namespace std;// Function prototypesvoid classInfo(int& numStudents, int& numExams);void getGrade(int numStudents, int numExams, double** grades);char getLetterGrade(double average);void courseGrade(int numStudents, int numExams, double** grades);int main() {    int choice;    int numStudents = 0, numExams = 0;    double** grades = nullptr;    do {
        cout << "Menu:" << endl;
        cout << "1. Enter class information" << endl;
        cout << "2. Enter grades" << endl;
        cout << "3. Display course grades" << endl;
        cout << "4. Exit" << endl;
        cout << "Enter your choice: ";
        cin >> choice;        switch (choice) {            case 1:                classInfo(numStudents, numExams);                // Dynamically allocate memory for grades array
                grades = new double*[numStudents];                for (int i = 0; i < numStudents; i++) {
                    grades[i] = new double[numExams];
                }                break;            case 2:                if (numStudents == 0 || numExams == 0) {
                    cout << "Error: Class information has not been entered yet." << endl;
                } else {                    getGrade(numStudents, numExams, grades);
                }                break;            case 3:                if (numStudents == 0 || numExams == 0) {
                    cout << "Error: Class information has not been entered yet." << endl;
                } else {                    courseGrade(numStudents, numExams, grades);
                }                break;            case 4:
                cout << "Exiting the program. Goodbye!" << endl;                // Deallocate memory for grades array
                if (grades != nullptr) {                    for (int i = 0; i < numStudents; i++) {                        delete[] grades[i];
                    }                    delete[] grades;
                }                break;            default:
                cout << "Invalid choice. Please try again." << endl;
        }

    } while (choice != 4);    return 0;
}void classInfo(int& numStudents, int& numExams) {
    cout << "Enter the number of students: ";
    cin >> numStudents;    while (numStudents <= 0) {
        cout << "Invalid number of students. Please enter a positive integer: ";
        cin >> numStudents;
    }

    cout << "Enter the number of exams: ";
    cin >> numExams;    while (numExams <= 0) {
        cout << "Invalid number of exams. Please enter a positive integer: ";
        cin >> numExams;
    }
}void getGrade(int numStudents, int numExams, double** grades) {
    cout << "Enter the grades for each student:" << endl;    for (int i = 0; i < numStudents; i++) {
        cout << "Student " << i + 1 << ": ";        for (int j = 0; j < numExams; j++) {
            cin >> grades[i][j];            // Validate grade (assume grade is between 0 and 100)
            while (grades[i][j] < 0 || grades[i][j] > 100) {
                cout << "Invalid grade. Please enter a grade between 0 and 100: ";
                cin >> grades[i][j];
            }
        }
    }
}char getLetterGrade(double average) {    if (average >= 90) {        return 'A';
    } else if (average >= 80) {        return 'B';
    } else if (average >= 70) {        return 'C';
    } else if (average >= 60) {        return 'D';
    } else {        return 'F';
    }
}void courseGrade(int numStudents, int numExams, double** grades) {
    cout << "Course grades:" << endl;    for (int i = 0; i < numStudents; i++) {        double total = 0;        for (int j = 0; j < numExams; j++) {
            total += grades[i][j];
        }        double average = total / numExams;        char letterGrade = getLetterGrade(average);
        cout << "Student " << i + 1 << ": Average = " << fixed << setprecision(2) << average << ", Letter Grade = " << letterGrade << endl;
    }
}

This C++ program implements the menu with options to enter class information, enter grades, display course grades, and exit the program. The user can select an option and perform the desired actions accordingly. The program uses functions to carry out the calculations, and error detection is included for the number of students and exams entered by the user.

Answer 3

Here's a C++ program that implements the menu and functions as described:

cppCopy code#include <iostream>#include <vector>#include <iomanip>using namespace std;// Global variables to store class informationint numStudents = 0;int numExams = 0;
vector<vector<double>> grades;// Function prototypesvoid classInfo();void getGrade();void courseGrade();int main() {    int choice;    do {        // Display menu
        cout << "Menu:" << endl;
        cout << "1. Enter class information" << endl;
        cout << "2. Enter grades" << endl;
        cout << "3. Display average and letter grade" << endl;
        cout << "4. Exit" << endl;
        cout << "Enter your choice (1-4): ";
        cin >> choice;        switch (choice) {            case 1:                classInfo();                break;            case 2:                if (numStudents == 0 || numExams == 0) {
                    cout << "Please enter class information first." << endl;
                } else {                    getGrade();
                }                break;            case 3:                if (numStudents == 0 || numExams == 0) {
                    cout << "Please enter class information first." << endl;
                } else {                    courseGrade();
                }                break;            case 4:
                cout << "Exiting program. Goodbye!" << endl;                break;            default:
                cout << "Invalid choice. Please try again." << endl;
        }

    } while (choice != 4);    return 0;
}void classInfo() {
    cout << "Enter the number of students in the class: ";
    cin >> numStudents;
    cout << "Enter the number of exams: ";
    cin >> numExams;    // Resize the 2D vector to hold the grades for each student and each exam
    grades.resize(numStudents, vector<double>(numExams, 0));
}void getGrade() {
    cout << "Enter the grades for each student:" << endl;    for (int i = 0; i < numStudents; i++) {
        cout << "Student " << i + 1 << ":" << endl;        for (int j = 0; j < numExams; j++) {
            cout << "Exam " << j + 1 << ": ";
            cin >> grades[i][j];
        }
    }
}void courseGrade() {
    cout << "Course grades:" << endl;    for (int i = 0; i < numStudents; i++) {        double sum = 0;        for (int j = 0; j < numExams; j++) {
            sum += grades[i][j];
        }        double average = sum / numExams;        char letterGrade;        if (average >= 90) {
            letterGrade = 'A';
        } else if (average >= 80) {
            letterGrade = 'B';
        } else if (average >= 70) {
            letterGrade = 'C';
        } else if (average >= 60) {
            letterGrade = 'D';
        } else {
            letterGrade = 'F';
        }

        cout << "Student " << i + 1 << " - Average: " << fixed << setprecision(2) << average << ", Grade: " << letterGrade << endl;
    }
}

Sample run with error detection for three students in the class and two exams:

mathematicaCopy codeMenu:1. Enter class information2. Enter grades3. Display average and letter grade4. ExitEnter your choice (1-4): 1Enter the number of students in the class: 3Enter the number of exams: 2Menu:1. Enter class information2. Enter grades3. Display average and letter grade4. ExitEnter your choice (1-4): 2Enter the grades for each student:Student 1:Exam 1: 85Exam 2: 78Student 2:Exam 1: 92Exam 2: 87Student 3:Exam 1: 75Exam 2: 68Menu:1. Enter class information2. Enter grades3. Display average and letter grade4. ExitEnter your choice (1-4): 3Course grades:Student 1 - Average: 81.50, Grade: BStudent 2 - Average: 89.50, Grade: BStudent 3 - Average: 71.50, Grade: CMenu:1. Enter class information2. Enter grades3. Display average and letter grade4. ExitEnter your choice (1-4): 4Exiting program. Goodbye!

The program allows the user to enter class information, then enter grades for each student, and finally display the average and letter grade for each student. Error detection is included to ensure that options 2 and 3 can only be selected after option 1 has been selected to enter class information.