C Program for Doubly Linked List Using Functions

1		#include<stdio.h>
2		#include<stdlib.h>
3		struct node
4		{
5		int data;
6		struct node *next;
7		struct node *prev;
8		};
9		struct node *header=NULL;
10		struct node *ptr=NULL,*temp=NULL;
11		void create();
12		void insert_at_front();
13		void insert_at_end();
14		void insert_at_middle();
15		void delete_at_front();
16		void delete_at_end();
17		void delete_at_middle();
18		void count();
19		void display();
20		void search();
21		int main()
22		{
23		int ch;
24		header=(struct node*)malloc(sizeof(struct node));
25		header->next=NULL;
26		header->prev=NULL;
27		ptr=header;
28		//clrscr();
29		printf("\n\n1.create \n2- insert at front\n3-insert at middle\n4-insert at end\n5-display\n6.delete_at_front\n7.delete_at_middle\n8.delete_at_end\\n9-exit");
30		while(1)
31		{
32		printf("\nenter ur choice : ");
33		scanf("%d",&ch);
34		switch(ch)
35		{
36		case 1: create();
37		break;
38		case 2: insert_at_front();
39		break;
40		case 3: insert_at_middle();
41		break;
42		case 4: insert_at_end();
43		break;
44		case 5: display();
45		break;
46		case 6: delete_at_front();
47		break;
48		case 7: delete_at_middle();
49		break;
50		case 8: delete_at_end();
51		break;
52		case 9: exit(0);
53		default: printf("wrong choice");
54		}
55		}
56		}
57		void create()
58		{
59		char ch;
60		while(1)
61		{
62		insert_at_end();
63		printf("if u want to continue press 'y' or 'n' :");
64		fflush(stdin);
65		scanf("%c",&ch);
66		if(ch=='y'||ch=='Y')
67		continue;
68		else
69		break;
70		}
71		}
72		void insert_at_front()
73		{
74		int ele;
75		struct node *new1;
76		new1=(struct node*)malloc(sizeof(struct node));
77		if(new1==NULL)
78		{
79		printf("out of space");
80		return;
81		}
82		printf("enter ele:");
83		scanf("%d",&ele);
84		new1->next=header->next;
85		header->next->prev=new1;
86		header->next=new1;
87		new1->prev=header;
88		new1->data=ele;
89		printf("inserted successfully");
90		}
91		int ele;
92		struct node *new1;
93		new1=(struct node*)malloc(sizeof(struct node));
94		if(new1==NULL)
95		{
96		printf("out of space");
97		return;
98		}
99		printf("enter ele:");
100		scanf("%d",&ele);
101		new1->next=header->next;
102		header->next->prev=new1;
103		header->next=new1;
104		new1->prev=header;
105		new1->data=ele;
106		printf("inserted successfully");
107		}
108		void insert_at_middle()
109		{
110		struct node *new1;
111		int ele;
112		int pos,count=0;
113		new1=(struct node*)malloc(sizeof(struct node));
114		ptr=header;
115		if(new1==NULL)
116		{
117		printf("out of space");
118		return;
119		}
120		printf("enter Inserted ele:");
121		scanf("%d",&ele);
122		printf("enter where it to_be inserted at what position_number:");
123		scanf("%d",&pos);
124		/* Calculate the no of elements in the list */
125		while(ptr->next!=NULL)
126		{
127		count++;
128		ptr=ptr->next;
129		}
130		/*Compare the entered positions number is valid or not using count the no.of elements in the list*/
131		if(count<pos)
132		{
133		printf("pos is out of range");
134		return;
135		}
136		ptr=header;
137		count=0;
138		/*Move the ptr upto particular entered position number*/
139		while(count<pos-1)
140		{
141		ptr=ptr->next;
142		count++;
143		}
144		new1->next=ptr->next;
145		new1->prev=ptr;
146		ptr->next->prev=new1;
147		ptr->next=new1;
148		new1->data=ele;
149		printf("inserted successfully");
150		}
151		void display()
152		{
153		ptr=header;
154		/* Check the List is Empty or not*/
155		if(ptr->next==NULL)
156		{
157		printf("list is empty");
158		return;
159		}
160		while(ptr->next!=NULL)
161		{
162		printf("%u,%d,%u -> ",ptr->next->prev,ptr->next->data,ptr->next->next);
163		ptr=ptr->next;
164		}
165		printf("NULL");
166		}
167		void delete_at_front()
168		{
169		ptr=header;
170		/* Check the List is Empty or not*/
171		if(ptr->next==NULL)
172		{
173		printf("list is empty deletion is not possible");
174		return;
175		}
176		temp=ptr->next;
177		ptr->next=ptr->next->next;
178		ptr->next->prev=ptr;
179		free(temp);
180		printf("deleted succssfully");
181		}
182		void delete_at_end()
183		{
184		ptr=header;
185		/* Check the List is Empty or not*/
186		if(ptr->next==NULL)
187		{
188		printf("list is empty deletion is not possible");
189		return;
190		}
191		/*Move the ptr upto last but one node*/
192		while(ptr->next->next!=NULL)
193		{
194		ptr=ptr->next;
195		}
196		temp=ptr->next;
197		ptr->next=NULL;
198		free(temp); /* Clear the Memory*/
199		printf("deleted succssfully");
200		}
201		void delete_at_middle()
202		{
203		int pos,count;
204		ptr=header;
205		/* Check the List is Empty or not*/
206		if(ptr->next==NULL)
207		{
208		printf("list is empty deletion is not possible");
209		return;
210		}
211		count=0;
212		/* Calculate the no.of elements in the list */
213		while(ptr->next!=NULL)
214		{
215		ptr=ptr->next;
216		count++;
217		}
218		printf("enter deleted position number:");
219		scanf("%d",&pos);
220		/*Compare the entered positions number is valid or not using count the no.of elements in the list*/
221		if(count<pos)
222		{
223		printf("position is_out of_range");
224		return;
225		}
226		ptr=header;
227		count=0;
228		/*Move the ptr upto particular entered position number*/
229		while(ptr->next->next!=NULL&&count<pos-1)
230		{
231		ptr=ptr->next;
232		count++;
233		}
234		temp=ptr->next;
235		ptr->next=ptr->next->next;
236		ptr->next->prev=ptr;
237		free(temp);
238		printf("deleted succssfully");
239		}
		/*OUTPUT:
		1.create
		2- insert at front
		3-insert at middle
		4-insert at end
		5-display
		6.delete_at_front
		7.delete_at_middle
		8.delete_at_end
		9-exit
		enter ur choice : 1
		enter Inserted ele:10
		inserted_successfully if u want_to_continue press 'y' or 'n' :n
		enter ur choice : 5
		28938256,10,0 -> NULL
		enter ur choice : 2
		enter ele:20
		inserted successfully
		enter ur choice : 5
		28938256,20,28938288 -> 28938320,10,0 -> NULL
		enter ur choice : 3
		enter Inserted ele:25
		enter where it to_be inserted at what position_number:2
		inserted successfully
		enter ur choice : 5
		28938256,20,28938352 -> 28938320,25,28938288 -> 28938352,10,0 -> NULL
		enter ur choice : 3
		enter Inserted ele:35
		enter where it to be inserted at what position number:3
		inserted successfully
		enter ur choice : 5
		28938256,20,28938352 -> 28938320,25,28938384 -> 28938352,35,28938288 -> 28938384,10,0 -> NULL
		enter ur choice : 6
		deleted succssfully
		enter ur choice : 5
		28938256,25,28938384 -> 28938352,35,28938288 ->  28938384,10,0 -> NULL
		enter ur choice : 7
		enter deleted position number:2
		deleted succssfully
		enter ur choice : 5
		28938256, 25, 28938288 -> 28938352,10,0 -> NULL
		enter ur choice : 8
		Deleted Succssfully
		enter ur choice : 5
		28938256,25,0 -> NULL
		enter ur choice : 9
		*/