import java.util.Scanner;

class Student
{
    int rollNo;
    String name;
    int marks1, marks2, marks3;
    int total;
    double percentage;
    String grade;

    void input(Scanner sc)
    {
        System.out.print("Enter Roll Number: ");
        rollNo = sc.nextInt();

        sc.nextLine();

        System.out.print("Enter Student Name: ");
        name = sc.nextLine();

        System.out.print("Enter Marks in Subject 1: ");
        marks1 = sc.nextInt();

        System.out.print("Enter Marks in Subject 2: ");
        marks2 = sc.nextInt();

        System.out.print("Enter Marks in Subject 3: ");
        marks3 = sc.nextInt();

        calculate();
    }

    void calculate()
    {
        total = marks1 + marks2 + marks3;

        percentage = total / 3.0;

        if(percentage >= 90)
            grade = "A+";

        else if(percentage >= 80)
            grade = "A";

        else if(percentage >= 70)
            grade = "B";

        else if(percentage >= 60)
            grade = "C";

        else if(percentage >= 40)
            grade = "D";

        else
            grade = "F";
    }

    void display()
    {
        System.out.println("--------------------------------");
        System.out.println("Roll Number : " + rollNo);
        System.out.println("Name        : " + name);
        System.out.println("Subject 1   : " + marks1);
        System.out.println("Subject 2   : " + marks2);
        System.out.println("Subject 3   : " + marks3);
        System.out.println("Total Marks : " + total);
        System.out.println("Percentage  : " + percentage + "%");
        System.out.println("Grade       : " + grade);
        System.out.println("--------------------------------");
    }
}

public class StudentManagement
{
    public static void main(String args[])
    {
        Scanner sc = new Scanner(System.in);

        Student s[] = new Student[50];

        int choice;
        int count = 0;
        int i, searchRoll;
        boolean found;

        do
        {
            System.out.println("\n================================");
            System.out.println("     STUDENT MANAGEMENT SYSTEM");
            System.out.println("================================");
            System.out.println("1. Add Student Record");
            System.out.println("2. Display All Students");
            System.out.println("3. Search Student");
            System.out.println("4. Display Topper");
            System.out.println("5. Display Class Average");
            System.out.println("6. Display Failed Students");
            System.out.println("7. Exit");
            System.out.println("================================");

            System.out.print("Enter Your Choice: ");
            choice = sc.nextInt();

            switch(choice)
            {
                case 1:

                    if(count < 50)
                    {
                        s[count] = new Student();

                        System.out.println("\nEnter Student Details:");

                        s[count].input(sc);

                        count++;

                        System.out.println("\nRecord Added Successfully!");
                    }
                    else
                    {
                        System.out.println("Student Limit Reached!");
                    }

                    break;

                case 2:

                    if(count == 0)
                    {
                        System.out.println("No Records Available!");
                    }
                    else
                    {
                        System.out.println("\nALL STUDENT RECORDS");

                        for(i = 0; i < count; i++)
                        {
                            s[i].display();
                        }
                    }

                    break;

                case 3:

                    System.out.print("Enter Roll Number to Search: ");
                    searchRoll = sc.nextInt();

                    found = false;

                    for(i = 0; i < count; i++)
                    {
                        if(s[i].rollNo == searchRoll)
                        {
                            System.out.println("\nStudent Found!");
                            s[i].display();

                            found = true;
                            break;
                        }
                    }

                    if(found == false)
                    {
                        System.out.println("Student Record Not Found!");
                    }

                    break;

                case 4:

                    if(count == 0)
                    {
                        System.out.println("No Student Records Available!");
                    }
                    else
                    {
                        int max = 0;

                        for(i = 1; i < count; i++)
                        {
                            if(s[i].total > s[max].total)
                            {
                                max = i;
                            }
                        }

                        System.out.println("\nCLASS TOPPER");
                        s[max].display();
                    }

                    break;

                case 5:

                    if(count == 0)
                    {
                        System.out.println("No Records Available!");
                    }
                    else
                    {
                        double sum = 0;

                        for(i = 0; i < count; i++)
                        {
                            sum = sum + s[i].percentage;
                        }

                        System.out.println("Class Average: " +
                        (sum / count) + "%");
                    }

                    break;

                case 6:

                    found = false;

                    System.out.println("\nFAILED STUDENTS");

                    for(i = 0; i < count; i++)
                    {
                        if(s[i].percentage < 40)
                        {
                            s[i].display();
                            found = true;
                        }
                    }

                    if(found == false)
                    {
                        System.out.println("No Failed Students!");
                    }

                    break;

                case 7:

                    System.out.println("\nThank You!");
                    System.out.println("Program Terminated.");

                    break;

                default:

                    System.out.println("Invalid Choice! Try Again.");
            }

        }while(choice != 7);

        sc.close();
    }
}