3. Student System

Main.java
package students;

import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        StudentSystem studentSystem = new StudentSystem();

        String[] input = readLine(scanner);
        while (!input[0].equals("Exit")) {
            studentSystem.parseCommand(input);
            input = readLine(scanner);
        }
    }
    private static String[] readLine(Scanner scanner) {
        return scanner.nextLine().split("\\s+");
    }
}

Student.java
package students;

public class Student {
    private String name;
    private int age;
    private double grade;

    public Student(String name, int age, double grade) {
        this.name = name;
        this.age = age;
        this.grade = grade;
    }

    public String getName() {
        return this.name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public int getAge() {
        return this.age;
    }

    public void setAge(int age) {
        this.age = age;
    }

    public double getGrade() {
        return this.grade;
    }

    public void setGrade(double grade) {
        this.grade = grade;
    }
}


StudentSystem.java
package students;

import java.util.HashMap;
import java.util.Map;

public class StudentSystem {
    private Map<String, Student> repo;

    public StudentSystem() {
        this.repo = new HashMap<>();
    }

    public Map<String, Student> getRepo() {
        return this.repo;
    }

    public void parseCommand(String[] args) {
        String firstArgument = args[0];
        String name = args[1];
        if (firstArgument.equals("Create")) {
            int age = Integer.parseInt(args[2]);
            double grade = Double.parseDouble(args[3]);
            if (!repo.containsKey(name)) {
                Student student = new Student(name, age, grade);
                repo.put(name, student);
            }
        } else if (firstArgument.equals("Show")) {
            if (repo.containsKey(name)) {
                StringBuilder builder = new StringBuilder();
                Student student = repo.get(name);
                builder.append(String.format("%s is %s years old.", student.getName(), student.getAge()));

                if (student.getGrade() >= 5.00) {
                    builder.append(" Excellent student.");
                } else if (student.getGrade() < 5.00 && student.getGrade() >= 3.50) {
                    builder.append(" Average student.");
                } else {
                    builder.append(" Very nice person.");
                }
                System.out.println(builder.toString());
            }
        }
    }
}