WRITE DOWN A C PROGRAM TO INSERT IN BEGINNING & END, DELETE A NODE IN BEGINNING & END, TRAVERSE FOR THE CIRCULAR - DOUBLY LINKED LIST (C-DLL) AND ALSO MODIFY A SPECIFIED NODE FOR THE CIRCULAR - DOUBLY LINKED LIST USING GLOBAL START VARIABLE & CALL BY REFERENCE & BY USING THE SWITCH CASE.

WRITE DOWN A C PROGRAM TO INSERT IN BEGINNING & END, DELETE A NODE IN BEGINNING & END, TRAVERSE FOR THE Circular - DOUBLY LINKED LIST (C-DLL) AND ALSO MODIFY A SPECIFIED NODE FOR THE CIRCULAR - DOUBLY LINKED LIST USING GLOBAL START VARIABLE & CALL BY REFERENCE & BY USING THE SWITCH CASE.

1. #include <stdio.h>
2. #include <stdlib.h>
3. #include <malloc.h>
4. struct node 
5. {
6. struct node *prev;
7. int data;
8. struct node *next;
9. };
10. struct node *start=NULL;
11. void create_nodebegining(int);
12. void create_nodeend(int);
13. void delete_nodebegining();
14. void delete_nodeend();
15. void modify(int,int);
16. void traverse();
17. int main()
18. {
19. int data,i,n,ch,data1;
20. printf("\n Enter The Value of data to be Entered:\n");
21. scanf("%d",&n);
22. for(i=0;i<n;i++)
23. {
24. printf("\n Enter The Value Should be Enter In Data of Node:\n");
25. scanf("%d",&data);
26. create_nodeend(data);
27. }
28. printf("\n Please Enter Your Choise \n ");
29. printf("\n Press 1 for Insert in Beginning \n Press 2 for Insert in end \n Press 3 Delete in Beginning \n Press 4 for delete in end \n Press 5 for modify \n press 6 for traverse \n");
30. scanf("%d",&ch);
31. switch(ch)
32. {
33. case 1:
34. printf("\n Enter The Value For Node Data:\n");
35. scanf("%d",&data);
36. create_nodebegining(data);
37. break;
38. case 2:
39. printf("\n Enter The Value For Node Data:\n");
40. scanf("%d",&data);
41. create_nodeend(data);
42. break;
43. case 3:
44. delete_nodebegining();
45. break;
46. case 4:
47. delete_nodeend();
48. break;
49. case 5:
50. printf("\n Enter The Data To be Modified:\n");
51. scanf("%d",&data1);
52. printf("\n Enter The Data Modified:\n");
53. scanf("%d",&data);
54. modify(data1,data);
55. break;
56. case 6:
57. traverse();
58. break;
60. }
61. traverse();
62. }
63. void create_nodeend(int x)
64. {
65. struct node *t,*t1;
66. t=(struct node*)malloc(sizeof(struct node));
67. t->prev=NULL;
68. t->data=x;
69. t->next=NULL;
70. if(start==NULL)
71. {
72. start=t;
73. t->next=start;
74. start->prev=t;
75. }
76. else
77. {
78. t1=start;
79. while(t1->next!=start)
80. {
81. t1=t1->next;
82. }
83. t->next=start;
84. t->prev=t1;
85. t1->next=t;
86. start->prev=t;
87. }
88. }
89. void create_nodebegining(int x)
90. {
91. struct node *t,*t1;
92. t1=start;
93. t=(struct node*)malloc(sizeof(struct node));
94. t->prev=NULL;
95. t->data=x;
96. t->next=NULL;
97. while(t1->next!=start)
98. {
99. t1=t1->next;
100. }
101. start->prev=t;
102. t->next=start;
103. start=t;
104. t1->next=start;
105. t->prev=t1;
106. traverse();
107. }
108. void delete_nodeend()
109. {
110. struct node *t,*t1;
111. t=start;
112. while(t->next!=start)
113. {
114. t1=t;
115. t=t->next;
116. }
117. free(t);
118. t1->next=start;
119. traverse();
120. }
121. void delete_nodebegining()
122. {
123. struct node *t,*t1;
124. t1=start;t=start;
125. while(t1->next!=start)
126. {
127. t1=t1->next;
128. }
129. free(start);
130. start=t->next;
131. start->prev=t1;
132. t1->next=start;
133. traverse();
134. }
135. void modify(int x,int y)
136. {
137. struct node *t;
138. t=start;
139. while(t->data!=x)
140. {
141. t=t->next;
142. }
143. t->data=y;
144. traverse();
145. }
146. 
     
147. void traverse()
148. {
149. struct node *t;
150. t=start;
151. while(t->next!=start)
152. {
153. printf("\n %d",t->data);
154. t=t->next;
155. }
156. printf("\n %d\n\n",t->data);
157. }