Article | Linked List In Java

Here is a Source Code for Linked List In Java.

1. import java.io.*;


2. class Node


3. {


4. Student data;


5. Node link;


6. Node()


7. {


8. data=null;


9. link=null;


10. }


11. public Node(Student data)


12. {


13. this.data=data;


14. link=null;


15. }


16. }


17. class LinkedList


18. {


19. Node head,newNode;


20. LinkedList()


21. {


22. head=null;


23. }


24. public void initList()


25. {


26. head=null;


27. }


28. public Node createNode(Student data)


29. {


30. Node node = new Node(data);


31. return node;


32. }


33. public int size()


34. {


35. int count=0;


36. Node p;


37. if(head==null)


38. {


39. return 0;


40. }


41. else


42. {


43. p=head;


44. while(p!=null)


45. {


46. count++;


47. p=p.link;


48. }


49. }


50. return count;


51. }


52. public void beforeX(Node newNode,Node x)


53. {


54. Node p=head;


55. while(p!=x.link)


56. {


57. p=p.link;


58. }


59. newNode.link=p;


60. x.link=newNode;


61. }


62. public void afterX(Node newNode,Node x)


63. {


64. Node p=head;


65. while(p!=x.link)


66. {


67. p=p.link;


68. }


69. newNode.link=p;


70. x.link=newNode;


71. }


72. public void insertAsFirst(Node newNode)


73. {


74. newNode.link=head;


75. head=newNode;


76. }


77. public void insertAsLast(Node newNode)


78. {


79. Node p = head;


80. while(p.link!=null)


81. p=p.link;


82. p.link=newNode;


83. }


84. public void relativeToX(Node newNode,int rel,Node x)


85. {


86. switch(rel)


87. {


88. case 1 : beforeX(newNode,x);


89. break;


90. case 2 : afterX(newNode,x);


91. break;


92. default: System.out.print("\n\nInvalid Option..... Check Syntax of relativeToX()");


93. }


94. }


95. public void insert(Node newNode,int pos,int reltox,Node x)


96. {


97. if(head==null)


98. {


99. head=newNode;


100. }


101. else


102. {


103. switch(pos)


104. {


105. case 0 : relativeToX(newNode,reltox,x);


106. break;


107. case 1 : insertAsFirst(newNode);


108. break;


109. case 2 : insertAsLast(newNode);


110. break;


111. }


112. }


113. }


114. public Node deleteAny(Node x)


115. {


116. Node p=head;


117. Node tmp;


118. tmp=x;


119. if(x==head)


120. {


121. head=x.link;


122. return tmp;


123. }


124. else


125. {


126. while(p.link!=x)


127. {


128. p=p.link;


129. }


130. p.link=x.link;


131. return tmp;


132. }


133. }


134. public Node deleteFirst()


135. {


136. Node tmp;


137. tmp=head;


138. head=head.link;


139. return tmp;


140. }


141. public Node deleteLast()


142. {


143. System.out.print("\n\n........Under Development.........");


144. return null;


145. }


146. public Node delete(int opt,Node x)


147. {


148. Node p=head;


149. Node tmp=null;


150. if(p==null)


151. {


152. System.out.print("\n\n!!!!!! LIST DOES NOT EXIST !!!!!!");


153. }


154. else


155. {


156. switch(opt)


157. {


158. case 1 : tmp=deleteFirst();


159. break;


160. case 2 : tmp=deleteLast();


161. break;


162. case 3 : tmp=deleteAny(x);


163. break;


164. default: System.out.print("\n\nDelete !!-- Wrong Option");


165. }


166. }


167. return tmp;


168. }


169. public Node search(int admno)


170. {


171. Node p = head;


172. Student s=null;


173. if(p==null)


174. System.out.print("\n\n!!!!!! LIST DOES NOT EXIST !!!!!!");


175. else


176. {


177. while(p!=null)


178. {


179. if(p.data.admno==admno)


180. return p;


181. p=p.link;


182. }


183. }


184. return null;


185. }


186. public void display()


187. {


188. Node p=head;


189. if(p==null)


190. System.out.print("\n\n!!!!!! LIST DOES NOT EXIST !!!!!!");


191. while(p!=null)


192. {


193. p.data.printData();


194. p=p.link;


195. }


196. }


197. }


198. class Student


199. {


200. public int admno;


201. private String name;


202. Student()


203. {


204. this.admno=0;


205. this.name="";


206. }


207. Student(int admno,String name)


208. {


209. this.admno=admno;


210. this.name=name;


211. }


212. public int getAdmno()


213. {


214. return admno;


215. }


216. public void printData()


217. {


218. System.out.print("\n\nAdmission Number : "+admno);


219. System.out.print("\n\nName : "+name);


220. }


221. }


222. class MyStudentListH


223. {


224. public static LinkedList ll=new LinkedList();


225. public static void deleteSubMenu()


226. {


227. int choice=0;


228. while(true)


229. {


230. System.out.print("\n\t\t\n\n\tDELETE\n\n");


231. System.out.print("\n\t1.FIRST\t\t:");


232. System.out.print("\n\t2.LAST\t\t:");


233. System.out.print("\n\t3.ANY NODE\t:");


234. System.out.print("\n\t4.MAIN MENU\t:");


235. BufferedReader br = new BufferedReader(new InputStreamReader(System.in));


236. try


237. {


238. System.out.print("\n\nEnter Your Choice : ");


239. choice=Integer.parseInt(br.readLine());


240. }


241. catch(Exception ex)


242. {


243. System.out.print("\nInput - Output Error !!!");


244. System.exit(1);


245. }


246. switch(choice)


247. {


248. case 1 : ll.delete(1,null);


249. break;


250. case 2 : ll.delete(2,null);


251. break;


252. case 3 : Node tmp=search();


253. if(tmp!=null)


254. {


255. ll.delete(3,tmp);


256. }


257. break;


258. case 4 : menu();


259. break;


260. default: System.out.print("\n\nInvalid Menu Option !!!!!!!!!");


261. }


262. }


263. }


264. public static void insertSubMenu()


265. {


266. int choice=0;


267. Student s=null;


268. Node newNode=null;


269. Node tmp;


270. while(true)


271. {


272. System.out.print("\n\t\t\n\n\tINSERT\n\n");


273. System.out.print("\n\t1.FIRST\t\t:");


274. System.out.print("\n\t2.LAST\t\t:");


275. System.out.print("\n\t3.BEFORE NODE X\t:");


276. System.out.print("\n\t4.AFTER NODE X\t:");


277. System.out.print("\n\t5.MAIN MENU\t:");


278. BufferedReader br = new BufferedReader(new InputStreamReader(System.in));


279. try


280. {


281. System.out.print("\n\nEnter Your Choice : ");


282. choice=Integer.parseInt(br.readLine());


283. if(choice!=5)


284. {


285. System.out.print("\n\n---Data to new Record-----");


286. System.out.print("\n\nEnter The Admission Number : ");


287. int admno=Integer.parseInt(br.readLine());


288. System.out.print("\n\nEnter Name : ");


289. String name = br.readLine();


290. s=new Student(admno,name);


291. newNode=ll.createNode(s);


292. }


293. }


294. catch(Exception ex)


295. {


296. System.out.print("\nInput - Output Error !!!");


297. System.exit(1);


298. }


299. switch(choice)


300. {


301. case 1 : System.out.print("\n\nInsert as First Node ");


302. ll.insert(newNode,1,0,null);


303. break;


304. case 2 : System.out.print("\n\nInsert as Last Node ");


305. ll.insert(newNode,2,0,null);


306. break;


307. case 3 : System.out.print("\n\nInsert before Node X ");


308. tmp=search();


309. if(tmp!=null)


310. {


311. ll.insert(newNode,0,1,tmp);


312. }


313. break;


314. case 4 : System.out.print("\n\nInsert after Node X ");


315. tmp=search();


316. if(tmp!=null)


317. {


318. ll.insert(newNode,0,2,tmp);


319. }


320. break;


321. case 5 : System.out.print("\n\nTo Main Menu ");


322. menu();


323. break;


324. default: System.out.print("\n\nInvalid menu option !!!!!");


325. }


326. }


327. }


328. public static Node search()


329. {


330. BufferedReader br = new BufferedReader(new InputStreamReader(System.in));


331. int admno=0;


332. Node res;


333. try


334. {


335. System.out.print("\n\n----Search Data-----");


336. System.out.print("\n\nEnter Admission number : ");


337. admno=Integer.parseInt(br.readLine());


338. }


339. catch(Exception ex)


340. {


341. System.out.print("\nInput - Output Error !!!");


342. System.exit(1);


343. }


344. res=ll.search(admno);


345. if(res==null)


346. {


347. System.out.print("\n\n--->Student Record Not Found");


348. }


349. else


350. {


351. System.out.print("\n\n--->Student Record Found");


352. res.data.printData();


353. }


354. return res;


355. }


356. public static void menu()


357. {


358. int choice=0;


359. while(true)


360. {


361. System.out.print("\n\t\t\n\n\tLINKED LIST\n");


362. System.out.print("\n\t1.INSERT\t:");


363. System.out.print("\n\t2.DELETE\t:");


364. System.out.print("\n\t3.DISPLAY\t:");


365. System.out.print("\n\t4.SEARCH\t:");


366. System.out.print("\n\t5.INITIALIZE\t:");


367. System.out.print("\n\t6.SIZE\t\t:");


368. System.out.print("\n\t7.EXIT\t\t:");


369. BufferedReader br = new BufferedReader(new InputStreamReader(System.in));


370. try


371. {


372. System.out.print("\n\nEnter Yor Choice : ");


373. choice=Integer.parseInt(br.readLine());


374. }


375. catch(Exception ex)


376. {


377. System.out.print("\nInput - Output Error !!!");


378. System.exit(1);


379. }


380. switch(choice)


381. {


382. case 1 : insertSubMenu();


383. break;


384. case 2 : deleteSubMenu();


385. break;


386. case 3 : ll.display();


387. break;


388. case 4 : Node tmp=search();


389. break;


390. case 5 : ll.initList();


391. System.out.print("\n\nList is Initialized");


392. break;


393. case 6 : System.out.print("\n\nNumber of items in the List : "+ll.size());


394. break;


395. case 7 : System.out.print("\nGOOD BYE.....\n\n");


396. System.exit(1);


397. default: System.out.print("\n\nInvalid menu Option !!!!!");


398. }


399. }


400. }


401. public static void main(String[] arg)


402. {


403. int n,i;


404. String name;


405. menu();


406. }


407. }

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