C++ (CP 123) TEST2 RE-SIT2 2023-2024 SOLVED INTERACTIVE

Question

Miss Wandiba is class teacher at Jitambue Secondary school at Ulanga district. He is used to have monthly examination on 28th of every month. In this digital era, he wants a simple computer program that will be able to store permanently and display the report of her students. For each student, the report will have the following information: all scores, total scores, average score, and GPA. The student must attempt a minimum of 7 examinations to have a complete report. The student can either sit for 7, 8, or 9 examinations. Suppose that the class has 50 students, write a C++ program that will:

a. Accept scores of all students and store them into array name scoredmark. The array should dynamic to support any entered within the range of 7⇐size⇐9.

b. Calculate sum and average, and find the grade from average marks.

c. For each student, the program should store sum, average score, and GPA into a file name report.txt.

d. Display data from report.txt on a screen.

Answer (Click to show)

#include <iostream>
#include <fstream>
#include <iomanip>
using namespace std;
 
// Function to calculate grade based on average marks
char calculateGrade(double average) {
    if (average >= 81) return 'A';
    else if (average >= 71) return 'B';
    else if (average >= 61) return 'C';
    else if (average >= 50) return 'D';
    else return 'F';
}
 
// Function to calculate GPA based on grade
double calculateGPA(char grade) {
    switch(grade) {
        case 'A': return 5.0;
        case 'B': return 4.0;
        case 'C': return 3.0;
        case 'D': return 2.0;
        case 'F': return 0.0;
        default: return 0.0;
    }
}
 
int main() {
    const int NUM_STUDENTS = 50;
    const int MIN_EXAMS = 7;
    const int MAX_EXAMS = 9;
    
    // Dynamic array for scores
    int** scoredmark = new int*[NUM_STUDENTS];
    int* examCounts = new int[NUM_STUDENTS];
    
    // Part a: Accept scores for all students
    for (int i = 0; i < NUM_STUDENTS; i++) {
        cout << "Enter number of exams for student " << (i + 1) 
             << " (7-9): ";
        cin >> examCounts[i];
        
        // Validate exam count
        while (examCounts[i] < MIN_EXAMS || examCounts[i] > MAX_EXAMS) {
            cout << "Invalid number! Enter between 7 and 9: ";
            cin >> examCounts[i];
        }
        
        // Allocate dynamic array for this student's scores
        scoredmark[i] = new int[examCounts[i]];
        
        cout << "Enter " << examCounts[i] << " scores for student " 
             << (i + 1) << ": ";
        for (int j = 0; j < examCounts[i]; j++) {
            cin >> scoredmark[i][j];
        }
    }
    
    // Part c: Open file for writing
    ofstream outFile("report.txt");
    if (!outFile) {
        cerr << "Error opening file for writing!" << endl;
        return 1;
    }
    
    // Write header to file
    outFile << "STUDENT REPORT\n";
    outFile << "==============\n\n";
    
    // Process each student
    for (int i = 0; i < NUM_STUDENTS; i++) {
        // Part b: Calculate sum and average
        int sum = 0;
        for (int j = 0; j < examCounts[i]; j++) {
            sum += scoredmark[i][j];
        }
        
        double average = static_cast<double>(sum) / examCounts[i];
        char grade = calculateGrade(average);
        double gpa = calculateGPA(grade);
        
        // Write to file
        outFile << "Student " << (i + 1) << ":\n";
        outFile << "Scores: ";
        for (int j = 0; j < examCounts[i]; j++) {
            outFile << scoredmark[i][j] << " ";
        }
        outFile << "\nTotal: " << sum;
        outFile << "\nAverage: " << fixed << setprecision(2) << average;
        outFile << "\nGrade: " << grade;
        outFile << "\nGPA: " << gpa << "\n\n";
    }
    
    outFile.close();
    cout << "\nData successfully written to report.txt\n";
    
    // Part d: Display data from file
    cout << "\n--- DISPLAYING REPORT FROM FILE ---\n";
    ifstream inFile("report.txt");
    string line;
    
    if (!inFile) {
        cerr << "Error opening file for reading!" << endl;
        return 1;
    }
    
    while (getline(inFile, line)) {
        cout << line << endl;
    }
    
    inFile.close();
    
    // Clean up dynamic memory
    for (int i = 0; i < NUM_STUDENTS; i++) {
        delete[] scoredmark[i];
    }
    delete[] scoredmark;
    delete[] examCounts;
    
    return 0;
}