Singly Linked List

Program : Singly Linked List

import java.io.*; //To implement I/O operations

class link //The class link

{

int data; //data item

link next; //next link in list



link(int id) //constructor

{

data=id; //initialize data

}



void displaylink() //To display the list

{

System.out.println("{"+data+"}");

}

} //end of class link

class linklist //The class linklist

{

link first; //ref to first link on list





linklist() //constructor

{

first=null; //no links on list yet

}



void create(int id) //To insert into the list

{

link l=new link(id); //make new link

l.next=first;

first=l;

} //End of function create



public void delete(int dt) //To delete from the list

{

link ct=first; //point to the beginning of the list

link pre=first; //point to the beginning of the list

if(first==null) //Check if list is empty

System.out.println("EMPTY LIST");

else if (first.data==dt)

first=first.next; //move to next link

else

{

while (ct.data!=dt)

{

pre=ct;

ct=ct.next;

}

pre.next=ct.next;

}

} //End of function delete



public void insert(int el,int da)

{

link ct=first; //point to the beginning of the list

link l=new link(el);

if (first==null) //Check if list is empty

{

first=l;

}

else

{

while (ct.data!=da)

{

ct=ct.next;

}

l.next=ct.next;

ct.next=l;

}

}

public void search(int ele) //Function to search for an element

{

int i=0;

link ct=first; //point to the beginning of the list

while (ct!=null)

{

if(ct.data==ele)

i=1;

ct=ct.next;

}

if(i==1)

System.out.println("THE SEARCHED ITEM IS EXIST IN THE LIST");

else

System.out.println("THE SEARCHED ITEM IS NOT EXIST IN THE LIST");

}



void displaylist() //Function to display the linkedlist

{

link current=first; //point to the beginning of the list

if (current==null) //Check if list is empty

{

System.out.println("EMPTY LIST");

}

while (current!=null)

{

current.displaylink();

current=current.next; //move to next link

}

}

}

class singlylinkedlist //The main class singlylinkedlist

{

//The main function

public static void main(String args[])throws IOException

{

char cc;

int ch=0;

linklist list=new linklist();

try

{

do

{

BufferedReader f=new BufferedReader(new InputStreamReader(System.in));

//Print Menu

System.out.println("1.CREATE THE LIST");

System.out.println("2.DELETE AN ELEMENT");

System.out.println("3.DISPLAY THE LIST");

System.out.println("4.INSERT AN ELEMENT");

System.out.println("5.SEARCH AN ELEMENT");

System.out.println("ENTER YOUR CHOICE");

ch=Integer.parseInt(f.readLine());

//Accepts choice

if (ch==1)

{

System.out.println("ENTER THE NUMBER OF ELEMENTS TO BE INSERTED");

int n=Integer.parseInt(f.readLine());

for(int i=0;i<n;i++)

{

System.out.println("ENTER THE NUMBER");

int x=Integer.parseInt(f.readLine());

list.create(x);

}

}

if (ch==2)

{

System.out.println("ENTER THE NUMBER TO BE DELETED");

int d=Integer.parseInt(f.readLine());

list.delete(d);

}

else if (ch==3)

{

System.out.println("ELEMENTS IN THE LIST ARE");

list.displaylist();

}

else if (ch==4)

{

System.out.println("ENTER THE NUMBER AND POSITION TO BE INSERTED");

int d1=Integer.parseInt(f.readLine());

int d2=Integer.parseInt(f.readLine());

list.insert(d1,d2);

}

if (ch==5)

{

System.out.println("ENTER THE NUMBER TO BE SEARCHED");

int se=Integer.parseInt(f.readLine());

list.search(se);

}

System.out.println();

System.out.println("DO YOU WANT TO CONTINUE(Y/N)");

cc=(char) f.read();

}

while(cc=='y');

}

catch(Exception e) //To catch any exceptions

{

}

} //End of main function

} //End of main class SinglyLinkedlist