Linked_list.c

#include<stdio.h>
#include<conio.h>
#include<stdlib.h>

//defining the structure
typedef struct nodetype
{
    int info;
    struct nodetype *next;
}node;

//function prototypes
void CreateEmptyList(node **head);
void TraverseInOrder(node *head);
void InsertAtBeginning(node **head, int item);
void TraverseInReverseOrder(node *head);
void InsertAtEnd(node **head, int item);
void InsertAfterElement(node *head, int item, int after);
node *Search(node *head, int item);
node *SearchInSorted(node *head, int item);
void DeleteFromBeginning(node **head);
void DeleteFromEnd(node **head);
void DeleteAfterElement(node *head, int item);

//main function
void main()
{
    node *head;
    int choice,element,after;
    CreateEmptyList(&head);
        printf("\nOperations available are:");
        printf("\n1.Insert at beginning \n2.Traverse in order \n3.Traverse in reverse order\n4.Insert at end\n5.Search\n6.Insert after element\n7.Search in sorted list\n8.Delete from beginning\n9.Delete from end\n10.Delete after element\n");

    while(1)
    {

           printf("Enter choice:");
        scanf("%d",&choice);
        switch(choice)
        {
            case 1:
                printf("Enter element:");
                scanf("%d",&element);
                InsertAtBeginning(&head, element);
                break;
            case 2:
                if(head==NULL)
                    printf("The list is empty");
                else
                    TraverseInOrder(head);
                break;
            case 3:
                if(head==NULL)
                    printf("The list is empty");
                else
                    TraverseInReverseOrder(head);
                break;
            case 4:
                printf("Enter element:");
                scanf("%d",&element);
                InsertAtEnd(&head,element);
                break;
            case 5:
                printf("Enter element:");
                scanf("%d",&element);
                printf("%d",Search(head,element));
                break;
            case 6:
                printf("Enter element after which to store:");
                scanf("%d",&after);
                printf("Enter element:");
                scanf("%d",&element);
                InsertAfterElement(head,element,after);
                break;
            case 7:
                printf("Enter element:");
                scanf("%d",&element);
                printf("%d",SearchInSorted(head,element));
                break;
            case 8:
                DeleteFromBeginning(&head);
                break;
            case 9:
                DeleteFromEnd(&head);
                break;
            case 10:
                printf("Enter element:");
                scanf("%d",&element);
                DeleteAfterElement(head,element);
                break;
            default:
                exit(0);
        }
    }
}

//Function definitions
void CreateEmptyList(node **head)
{
    *head = NULL;
}

void InsertAtBeginning(node **head, int item)
{
    node *ptr;
    ptr = (node*)malloc(sizeof(node));
    ptr->info = item;
    if(*head==NULL)
        ptr->next=NULL;
    else
        ptr->next=*head;
    *head=ptr;
}

void TraverseInOrder(node *head)
{
    while(head!=NULL)
    {
        printf("%d\n", head->info);
        head = head->next;
    }
}

void TraverseInReverseOrder(node *head)
{
    if(head->next!=NULL)
        TraverseInReverseOrder(head->next);
    printf("%d\n",head->info);
}

void InsertAtEnd(node **head, int item)
{
    node *ptr, *loc;
    ptr=(node*)malloc(sizeof(node));
    ptr->info=item;
    ptr->next=NULL;
    if(*head==NULL)
        *head=ptr;
    else
    {
        loc=*head;
        while(loc->next!=NULL)
            loc=loc->next;
        loc->next=ptr;
     }
}

node *Search(node *head, int item)
{
    while((head!=NULL) && (head->info!=item))
        head=head->next;
    return head;
}

node *SearchInSorted(node *head, int item)
{
    while(head!=NULL)
    {
        if(item < head->info)
            return NULL;
        else if(head->info==item)
            return head;
        else
            head=head->next;
    }
    return NULL;
}

void InsertAfterElement(node *head, int item, int after)
{
    node *ptr, *loc;
    loc=Search(head,after);
    if(loc==(node*)NULL)
        return;
    ptr=(node*)malloc(sizeof(node));
    ptr->info=item;
    ptr->next=loc->next;
    loc->next=ptr;
}

void DeleteFromBeginning(node **head)
{
    node *ptr;
    if(*head==NULL)
        return;
    else
    {
        ptr=*head;
        *head=(*head)->next;
        free(ptr);
    }
}

void DeleteFromEnd(node **head)
{
    node *ptr,*loc;
    if(*head==NULL)
        return;
    else if((*head)->next==NULL)
    {
        ptr=*head;
        *head=NULL;
        free(ptr);
    }
    else
    {
        loc=*head;
        ptr=(*head)->next;
        while(ptr->next!=NULL)
        {
            loc=ptr;
            ptr=ptr->next;
        }
        loc->next=NULL;
        free(ptr);
    }
}

void DeleteAfterElement(node *head, int item)
{
    node *ptr,*loc;
    loc=Search(head,item);
    if(loc==(node*)NULL)
        return;
    ptr=loc->next;
    loc->next=ptr->next;
    free(ptr);
}