main.cpp

#include <bits/stdc++.h>
using namespace std;

// Constants
const int MAX_STUDENTS = 100;
const int SUBJECT_COUNT = 3;

// Student Data
struct Student {
    int ID;
    string Name;
    char Gender;
    int Age;
    int Marks[SUBJECT_COUNT];
    float Average;
    char Grade;
};

// Function prototypes
float Calculate_Average(int Marks[], int Size);
char Calculate_Grade(float Average);
void Input_one_Student(Student &Cur_Student);
void Input_Students(Student Students[], int &Count);
void Display_Header();
void Display_Student(Student Cur_Student);
void Display_All_Students(Student Students[], int Count);
void Run_Student_System();

// Function Definitions

// Calculate Average
float Calculate_Average(int Marks[], int Size) {
    float sum = 0;
    for (int i = 0; i < Size; ++i) {
        sum += Marks[i];
    }
    return sum / Size;
}

// Calculate Grade
char Calculate_Grade(float 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';
}

// Input one student
void Input_one_Student(Student &Cur_Student) {
    cout << "Enter Student ID: ";
    cin >> Cur_Student.ID;
    cin.ignore(); // Clear the newline character

    cout << "Enter Student Name: ";
    getline(cin, Cur_Student.Name);

    cout << "Enter Gender (M/F): ";
    cin >> Cur_Student.Gender;

    cout << "Enter Age: ";
    cin >> Cur_Student.Age;

    cout << "Enter Marks for " << SUBJECT_COUNT << " Subjects:" << endl;
    for (int i = 0; i < SUBJECT_COUNT; ++i) {
        cout << "Subject " << i + 1 << ": ";
        cin >> Cur_Student.Marks[i];
    }

    // Calculate Average and Grade
    Cur_Student.Average = Calculate_Average(Cur_Student.Marks, SUBJECT_COUNT);
    Cur_Student.Grade = Calculate_Grade(Cur_Student.Average);
}

// Input multiple students
void Input_Students(Student Students[], int &Count) {
    char choice;
    do {
        cout << "Enter Student Data #" << (Count + 1) << endl;
        Input_one_Student(Students[Count]);
        Count++;

        if (Count >= MAX_STUDENTS) {
            cout << "Reached Maximum Student Capacity" << endl;
            break;
        }

        cout << "Add another student? (Y/N): ";
        cin >> choice;
    } while (choice == 'Y' || choice == 'y');
}

// Display table header
void Display_Header() {
    cout << left << setw(5) << "ID" << setw(15) << "Name" << setw(8) << "Gender" << setw(5) << "Age";
    for (int i = 0; i < SUBJECT_COUNT; ++i) {
        cout << setw(6) << "M" << (i + 1);
    }
    cout << setw(8) << "Avg" << setw(6) << "Grade" << endl;
    cout << "----------------------------------------------------------" << endl;
}

// Display single student
void Display_Student(Student Cur_Student) {
    cout << left << setw(5) << Cur_Student.ID << setw(15) << Cur_Student.Name << setw(8) << Cur_Student.Gender << setw(5) << Cur_Student.Age;
    for (int i = 0; i < SUBJECT_COUNT; ++i) {
        cout << setw(6) << Cur_Student.Marks[i];
    }
    cout << fixed << setprecision(2) << setw(8) << Cur_Student.Average << setw(6) << Cur_Student.Grade << endl;
}

// Display all students
void Display_All_Students(Student Students[], int Count) {
    cout << "\n===== Student Records =====\n";
    Display_Header();
    for (int i = 0; i < Count; ++i) {
        Display_Student(Students[i]);
    }
}

// Control function
void Run_Student_System() {
    Student Students[MAX_STUDENTS];
    int Student_Count = 0;

    Input_Students(Students, Student_Count);
    Display_All_Students(Students, Student_Count);
}

// Main function
int main() {
    Run_Student_System();
    return 0;
}