✍️عاصم ناجي

✍️@AsemNaji

class Query{
String table;
String columns;
void setTable(String table){
this.table = table;
}
void setColumns(String columns){
this.columns = columns;
}
@Override
public String toString(){
return "SELECT " + columns + " FROM " + table;
}

Query q = new Query();
q.setTable("users");
q.setColumns("*");
System.out.print(q);

Query q = new Query();
q.select("*").from("users");

class Query{
String table;
String columns;

Query from(String table){
this.table = table;
return this;
}
Query select(String columns){
this.colmns = columns;
return this;
}
@Override
public String toString(){
return "SELECT " + columns + " FROM " + table;
}

Query.select("*").from("users");

static Query select(String columns){
Query q = new Query();
q.columns = columns;
return q;
}

private Query(){}

String name = "asem";
if(name.substring(0, 1).toUpperCase().equals("A")){
System.out.print(name + " starts with A or a");
}

آلَلَهّمً يَ مًحًوٌلَ آلَآحًوٌآلَ، حًوٌلَ حًآلَيَ آلَﮯ أفُضلَ حًآلَ 🤍🤲

ماهي القوائم المرتبطة«LinkedList»

الشكل العام لبنية ال LinkedList بلغة جافا :

class Node {
    int data;
    Node next;
    
    Node(int data) {
        this.data = data;
        this.next = null;
    }
}

مميزات LinkedList :

عيوبها :

class Node<T> {
    T data;
    Node next;
    
  public  Node(T data) {
        this.data = data;
        this.next = null;
    }
}

class LinkedList{
Node head ;// عقدة تمثل بداية القائمة 

public<T> void  insert(T element){
 Node node = new Node(element);//تعريف العقدة التي سيتم اضافتها
    if(head == null) // فحص ان القائمة فارغة
        head = node;
else
{
    Node current = head ;//  يبدأ هذا المتغير من head
while(current.next != null )// loop لكي يمر  على جميع العقد
        current = current. next; 

current.next = n;//المؤشر تبع اخر عقدة بيكون يشير الى العقدة الجديد
} 
} 
}

  public void InsertFirst(T element) {
   Node node = new Node (element); 
    node.next = head;
    head = node;     
    
}

  public void InsertatPosition(T element , int position){
   Node node = new Node (element); 
   if (position == 0){
       InsertFirst(element);// نضيفة بواسطة دالة الاضافة للبداية
      return //للخروج من الدالة
  } 

   Node  current = head; 
   int counter = 1;
    
  while(current !=null  && counter < position-1){ 
        current = current. next; 
        counter ++; 
  } 

  if(current == null ){
      System. out. println("position is not found ! "); 
     return} 

//inserttge new node
   node. next = current. next; 
   current. next = node; 
}

  public void delete(T element) {
     if(head == null ) return; 

     if(head.data == element){
          head = head. next; 
          return; 
     }
 
      Node current = head; 
      while(current.next != null){
             if(current.next.data == element ) 
                   current.next = current. next. next; 
                    return; 
    }
current  = current. next ; 
}

  public void InsertFirst(T element) {
     Node current  = head; 
     while (current != null){
            System. out. println(current.dat+" —» "); 
            current = current. next ; 
  } 
     System. out. println(" null ");  
}

  public void InsertFirst(LinkedList list2 ) {
  if(head == null ){
     head = list2.next ; 
     return ; 
} 
  Node current  = head; 
  while (current.next != null ){
            current = current. next.; 
} 
current. next  =  list2.haed;   
}