c code for single linked list
implement single linked list
Write a menu-driven program to perform the following operations in a single linked list by using suitable user-defined functions for each case. a) Traversal of the list. b) Check if the list is empty. c) Insert a node at a certain position (at beginning/end/any position). d) Delete a node at a certain position (at the beginning/end/any position). e) Delete a node for the given key. f) Count the total number of nodes. g) Search for an element in the linked list. Verify & validate each function from the main method
Code
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
struct node
{
int data;
struct node *next;
};
int init_count(struct node *r)
{
int count = 0;
while (r)
{
r = r->next;
count++;
}
return count;
}
void display(struct node *r)
{
printf("elements of list are : ");
while (r)
{
printf("%d ---> ", r->data);
r = r->next;
}
printf("NULL\n");
}
struct node *create(struct node *head)
{
struct node *t, *p;
int n;
if (head == NULL)
{
t = (struct node *)malloc(sizeof(struct node));
printf("enter the node: \n");
scanf("%d", & t->data);
t->next = NULL;
head = t;
}
if (head != NULL)
{
do
{
t = (struct node *)malloc(sizeof(struct node));
printf("enter the node: \n");
scanf("%d", &t->data);
t->next = NULL;
p = head;
while (p->next != NULL)
{
p = p->next;
}
p->next = t;
printf("do you want to add more node press 1 for yes, 0 for no. ");
scanf("%d", &n);
} while (n);
}
return head;
}
struct node *insert_beginning(struct node *head)
{
struct node *t;
t = (struct node *)malloc(sizeof(struct node));
printf("enter the node: ");
scanf("%d", &t->data);
t->next = head;
return t;
}
struct node *insert_end(struct node *head)
{
struct node *t, *p;
t = (struct node *)malloc(sizeof(struct node));
printf("enter the node: \n");
scanf("%d", &t->data);
p = head;
while (p->next != NULL)
{
p = p->next;
}
p->next = t;
t->next = NULL;
return head;
}
struct node *insert_any_index(struct node *head)
{
int index;
printf("enter position or index\n");
scanf("%d", &index);
if (index > 0 && index < init_count(head))
{
int i = 1;
struct node *t, *p;
t = (struct node *)malloc(sizeof(struct node));
printf("enter the node: \n");
scanf("%d", &t->data);
p = head;
while (i != index)
{
p = p->next;
i++;
}
t->next = p->next;
p->next = t;
return head;
}
else
{
printf("INVALID INDEX\n");
}
}
struct node *delete_beginning(struct node *head)
{
struct node *t = head;
head = head->next;
free(t);
return head;
}
struct node *delete_end(struct node *head)
{
struct node *t, *p;
p = head;
while (p->next->next != NULL)
{
p = p->next;
}
t = p->next;
p->next = NULL;
free(t);
return head;
}
struct node *delete_any_index(struct node *head)
{
int index;
printf("enter position or index\n");
scanf("%d", &index);
struct node *p = head;
struct node *q = head->next;
printf("%d", index);
if (index > 0 && index < init_count(head))
{
for (int i = 1; i < index - 1; i++)
{
p = p->next;
q = q->next;
}
p->next = q->next;
free(q);
return head;
}
else
{
printf("INVALID INDEX\n");
}
}
struct node *delete_key(struct node *head, int key)
{
struct node *p = head;
struct node *q = head->next;
p = head;
while (q->data != key && q->next != NULL)
{
p = p->next;
q = q->next;
}
if (q->data == key)
{
p->next = q->next;
free(q);
}
return head;
}
int main()
{
int c, n, index, key, count, l, xd = 0;
struct node *head = NULL, *p;
head = create(head);
printf("\n\n\n");
option:
printf("\n\n*********OPTIONS**********\n");
printf("1) Traversal of the list.\n");
printf("2) Check if the list is empty.\n");
printf("3) Insert a node at the certain position.\n");
printf("4) Delete a node at the certain position.\n");
printf("5) Delete a node for the given key.\n");
printf("6) Count the total number of nodes.\n");
printf("7) Search for an element in the linked list.\n");
printf("8) exit.\n");
printf("\nenter your choice: ");
scanf("%d", &c);
switch (c)
{
case 1:
display(head);
goto option;
break;
case 2:
if (head == NULL)
{
printf("empty linked list\n");
}
else
{
printf("not empty\n");
}
goto option;
break;
case 3:
option1:
printf("select from the list to perform\n");
printf("1)insert at beginning----> enter 1\n");
printf("2)insert at end----> enter 2\n");
printf("3)insert at any position except beginning and end----> enter 3\n");
printf("\n0-> to go back\n");
scanf("%d", &n);
switch (n)
{
case 0:
goto option;
case 1:
head = insert_beginning(head);
goto option1;
break;
case 2:
head = insert_end(head);
goto option1;
break;
case 3:
head = insert_any_index(head);
goto option1;
break;
default:
printf("INVALID / prev menu\n");
}
goto option;
break;
case 4:
option2:
printf("select from the list to perform\n");
printf("1)delete at beginning----> enter 1\n");
printf("2)delete at end----> enter 2\n");
printf("3)delete at any position except beginning and end----> enter 3\n");
printf("\n0-> to go back\n");
scanf("%d", &n);
switch (n)
{
case 0:
goto option;
case 1:
head = delete_beginning(head);
goto option2;
break;
case 2:
head = delete_end(head);
goto option2;
break;
case 3:
head = delete_any_index(head);
goto option2;
break;
default:
printf("INVALID\n");
}
goto option;
break;
case 5:
printf("enetr the key\n");
scanf("%d", &key);
head = delete_key(head, key);
goto option;
break;
case 6:
count = 0;
p = head;
while (p != NULL)
{
count++;
p = p->next;
}
printf("number of nodes are : %d\n", count);
goto option;
break;
case 7:
printf("enetr the key\n");
scanf("%d", &key);
p = head;
while (p != NULL)
{
if (p->data == key)
{
printf("node found : %d\n", key);
xd = 1;
}
p = p->next;
}
if (xd == 0)
{
printf("node not found\n");
}
goto option;
break;
case 8:
exit(0);
default:
printf("INVALID INPUT// exit\n");
goto option;
}
return 0;
}