import java.util.Locale;
import java.util.Scanner;

public class hmd2 {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);

        System.out.print("Enter a string: ");
        String input = scanner.nextLine();

        boolean running = true;

        while (running) {
            System.out.println("\nChoose an operation:");
            System.out.println("1. Get a character at a specific index (charAt)");
            System.out.println("2. Get the length of the string (length)");
            System.out.println("3. Create a substring from a start index (substring)");
            System.out.println("4. Create a substring from start to end indices (substring)");
            System.out.println("5. Compare the string with another string (equals)");
            System.out.println("6. Check if the string is empty (isEmpty)");
            System.out.println("7. Concatenate strings (concat)");
            System.out.println("8. Replace a character with another (replace)");
            System.out.println("9. Split the string into words (split)");
            System.out.println("10. Split the string into words with a limit (split with limit)");
            System.out.println("11. Get the string from the constant pool (intern)");
            System.out.println("12. Find the index of a character (indexOf)");
            System.out.println("13. Find the index of a character from a specific position (indexOf with start index)");
            System.out.println("14. Find the index of a substring (indexOf substring)");
            System.out.println("15. Find the index of a substring from a specific position (indexOf substring with start index)");
            System.out.println("16. Convert the string to lowercase (toLowerCase)");
            System.out.println("17. Convert the string to lowercase with locale (toLowerCase with Locale)");
            System.out.println("18. Convert the string to uppercase (toUpperCase)");
            System.out.println("19. Convert the string to uppercase with locale (toUpperCase with Locale)");
            System.out.println("20. Trim whitespace from the string (trim)");
            System.out.println("21. Exit");
            System.out.print("Enter your choice: ");

            int choice = scanner.nextInt();
            scanner.nextLine();

switch (choice) {
                case 1:
                    System.out.print("Enter the index: ");
                    int index = scanner.nextInt();
                    if (index >= 0 && index < input.length()) {
                        System.out.println("Character at index " + index + " is: " + input.charAt(index));
                    } else {
                        System.out.println("Invalid index.");
                    }
                    break;
                case 2:
                    System.out.println("Length of the string: " + input.length());
                    break;
                case 3:
                    System.out.print("Enter the starting index: ");
                    int start = scanner.nextInt();
                    if (start >= 0 && start < input.length()) {
                        System.out.println("Substring: " + input.substring(start));
                    } else {
                        System.out.println("Invalid start index.");}
                    break;
                case 4:
                    System.out.print("Enter the starting index: ");
                    start = scanner.nextInt();
                    System.out.print("Enter the ending index (exclusive): ");
                    int end = scanner.nextInt();
                    if (start >= 0 && end <= input.length() && start < end) {
                        System.out.println("Substring: " + input.substring(start, end));
                    } else {
                        System.out.println("Invalid indices.");
                    }
                    break;
                case 5:
                    System.out.print("Enter another string to compare: ");
                    String another = scanner.nextLine();
                    System.out.println("Strings are equal: " + input.equals(another));
                    break;
                case 6:
                    System.out.println(input.isEmpty() ? "The string is empty." : "The string is not empty.");
                    break;
                case 7:
                    System.out.print("Enter another string to concatenate: ");
                    String secondInput = scanner.nextLine();
                    System.out.println("Concatenated string: " + input.concat(secondInput));
                    break;
                case 8:
                    System.out.print("Enter the character to replace: ");
                    char oldChar = scanner.next().charAt(0);
                    System.out.print("Enter the new character: ");
                    char newChar = scanner.next().charAt(0);
                    input = input.replace(oldChar, newChar);
                    System.out.println("Updated string: " + input);
                    break;
                case 9:
                    String[] words = input.split(" ");
                    System.out.println("Words:");
                    for (String word : words) {
                        System.out.println(word);
                    }
                    break;
                case 10:
                    System.out.print("Enter the maximum number of parts: ");
                    int limit = scanner.nextInt();
                    String[] parts = input.split(" ", limit);
                    System.out.println("Parts:");
                    for (String part : parts) {
                        System.out.println(part);
                    }
                    break;
                case 11:
                    input = input.intern();
                    System.out.println("The string is now stored in the constant pool.");
                    break;

case 12:
                    System.out.print("Enter the character to search for: ");
                    char searchChar = scanner.next().charAt(0);
                    int position = input.indexOf(searchChar);
                    System.out.println(position != -1 ? "Found at position: " + position : "Character not found.");
                    break;
                case 13:
                    System.out.print("Enter the character to search for: ");
searchChar = scanner.next().charAt(0);
                    System.out.print("Enter the starting index for the search: ");
                    int fromIndex = scanner.nextInt();
                    position = input.indexOf(searchChar, fromIndex);
                    System.out.println(position != -1 ? "Found at position: " + position : "Character not found.");
                    break;
                case 14:
                    System.out.print("Enter the substring to search for: ");
                    String substring = scanner.nextLine();
                    position = input.indexOf(substring);
                    System.out.println(position != -1 ? "Found at position: " + position : "Substring not found.");
                    break;
                case 15:
                    System.out.print("Enter the substring to search for: ");
                    substring = scanner.nextLine();
                    System.out.print("Enter the starting index for the search: ");
                    fromIndex = scanner.nextInt();
                    position = input.indexOf(substring, fromIndex);
                    System.out.println(position != -1 ? "Found at position: " + position : "Substring not found.");
                    break;
                case 16:
                    System.out.println("String in lowercase: " + input.toLowerCase());
                    break;
                case 17:
                    System.out.println("String in lowercase (with locale): " + input.toLowerCase(Locale.getDefault()));
                    break;
                case 18:
                    System.out.println("String in uppercase: " + input.toUpperCase());
                    break;
                case 19:
                    System.out.println("String in uppercase (with locale): " + input.toUpperCase(Locale.getDefault()));
                    break;
                case 20:
                    System.out.println("Trimmed string: '" + input.trim() + "'");
                    break;
                case 21:
                    System.out.println("Exiting the program...");
                    running = false;
                    break;
                default:
                    System.out.println("Invalid choice. Please try again.");}}}}

✅لخطوة الأولى: المقدمة إلى البرمجة كائنية التوجه (OOP

✅الخطوه الثانيه:
راح نكتب اول برنامج بالoop وويشرحه بالتفصيل الممل واخر شي راح يشرح Access modifiers
وتعتبر من اهم اساسيات oop

لحد لهنا ضروري تفهمهن حتلو تعيد الشرح اكثر من مره وكلش عادي اذا مافهمت مره ومرتين لان ماده جديده فه اكيد ماتكون سهله الفهم

✅الخطوه الثالثه
راح يشرح .
Constructor
بالانواعه الاربعه مع امثله
و
Method Overloading

✅ الخطوه الرابعه ونووب اخذنا
static keywords
هنه وانواعه مع امثله

✅الخطوه الخامسه
واخر موضوع راح ناخذه بالكورس الاول وهوه
الوراثه
inheritance

هذا مسار يخص كلشي اخذنا والشرح كلش مقارب للملازم تكدرون تعتمدون عليه واكيد راح ننزل امثله بكل المواضيع بالايام الجايه وضروري ادرسون لان مابقه شي عن نهايه الكورس الاول والماده لحد الان زينه

واكيد لو لكيت شرح افضل راح انزله الكم

ملخص مفاهيم :

Class Area {
  private int Bass = 10;
  private int Hight = 20

  public getPrivateBase( ) {
  return Base;
  }

  public getPrivateHight( ) { 
  return Hight;
  }
}

class clSum
{
    public int SumTowNumbers(int Number1,int Number2)
    {
        return Number1 + Number2;
    }

    public double SumTowNumbers(double Number1, double Number2)
    {
        return Number1 + Number2;
    }

    public double SumTowNumbers(double Number1, int Number2)
    {
        return Number1 + Number2;
    }

    public double SumTowNumbers(int Number1, double Number2)
    {
        return Number1 + Number2;
    }

}
public class Main
{

    public static void main(String[] args)
    {
        clSum Sum = new clSum();

        System.out.println("1) Sum = " + Sum.SumTowNumbers(1,1)); // 2
        System.out.println("2) Sum = " + Sum.SumTowNumbers(1.3,1)); // 2.3
        System.out.println("3) Sum = " + Sum.SumTowNumbers(1,1.5)); // 2.5
        System.out.println("4) Sum = " + Sum.SumTowNumbers(2.2,3.3)); // 5.5

    }

}

class Example {
    void displayMessage() {
        System.out.println("Method called");
    }
}

public class Main {
    public static void main(String[] args) {
        Example obj = new Example();  // Constructor is called (default in this case)
        obj.displayMessage();  // Method is called
        obj.displayMessage();  // Method is called again
    }
}

class Example {
    void displayMessage() {
        System.out.println("Method called");
    }
}

public class Main {
    public static void main(String[] args) {
        Example obj = new Example();  // Constructor is called (default in this case)
        obj.displayMessage();  // Method is called
        obj.displayMessage();  // Method is called again
    }
}

class clCar
{
   // Default Constructor
   public clCar( ) {
   this ( "Helo world" ); // Constructor Chaining to public clCar(String Text)
   }
   
   // Parameterized Constructor
   public clCar(String Text) {
   System.out.println(Text); 
   }

}

class clCar
{

   // Parameterized Constructor
   public clCar(String Text) {
   System.out.println(Text); 
   }

   // Default Constructor
   public clCar( ) {
   this ( "Helo world" ); // Constructor Chaining to public clCar(String Text)
   }
   
}

import java.util.Scanner;

class clEmployee
{
    public clEmployee(String MyName)
    {
        System.out.println("\nMay Name is: " + MyName);
    }

    public clEmployee()
    {
        this("Ali");
        System.out.println("By using Constructor Chaining");
    }

}
public class Main
{

    public static void main(String[] args)
    {
        clEmployee Employee1,Employee2 ;

        Employee1 = new clEmployee();

        System.out.println("\n---------------------");
        Employee2 = new clEmployee("Abdulhamid");
        System.out.println("Using same class but does'nt use Chaining , we use Parameterized Constructor");
    }

}

مختصر هذا الكود انو نفس الكلاس الي سوينه بيه  Chaining نكدر نستعمله وندخل للكلاس مرة ثانية بأنشاء كائن جديد .

class clStudent
{
    String name;
    int age;

    // No-argument Constructor
    public clStudent()
    {
        this.name = "Unknown";
        this.age = 0;
    }

    // Parameterized constructor with one parameter
    public clStudent(String name)
    {
        this.name = name;
        this.age = 0;
    }

    // Parameterized constructor with Two parameter
    public clStudent(String name, int age)
    {
        this.name = name;
        this.age = age;
    }

    public void display()
    {
        System.out.println("Name: " + name + ", Age: " + age);
    }

}

public class Main
{

    public static void main(String[] args)
    {

        clStudent student1 = new clStudent(); // argument
        clStudent student2 = new clStudent("Ali"); // argument
        clStudent student3 = new clStudent("Mohammed", 20); // argument

        System.out.println();
        student1.display(); // Name: Unknown, Age: 0
        student2.display(); // Name: Ali, Age: 0
        student3.display(); // Name: Mona, Age: 20
    }
}