Doubly_linklist

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

typedef struct node
{

    int a;
    char ch;
    struct node*next;
    struct node*previous;
} node;

node*head=NULL,*tail=NULL;


void insert_at_first(int aN, char chN)
{
    node *N=(node*)malloc(sizeof(node));
    N->a=aN;
    N->ch=chN;
    N->next=NULL;
    N->previous=NULL;
    if(head==NULL)
    {
        head=N;
        return;
    }
    N->next=head;
    head->previous=N;
    head=N;
}


void insert_at_end(int aN,char chN)
{

    node*N=(node*)malloc(sizeof(node));
    N->a=aN;
    N->ch=chN;
    N->next=NULL;
    N->previous=NULL;
    node*list=head;
    if(head==NULL)
    {
        head=N;
    }
    else
    {
        while(list->next!=NULL)
        {
            list=list->next;
            N->previous=list;
        }
        list->next=N;
        N->next=NULL;
        N->previous=list;


    }

}


void insert_nth(int n,int aN,char chN)
{
    node *N=(node*)malloc(sizeof(node));
    N->a=aN;
    N->ch=chN;
    N->next=NULL;
    N->previous=NULL;
    if(n==1)
    {
        N->previous=NULL;
        N->next=head;
        head=N;

        return;
    }
    else
    {
        node*list=head;
        n=n-2;
        while(n!=0&&list->next!=NULL)
        {
            list=list->next;
            n--;
        }
        N->next=list->next;
        if(list->next !=NULL)
        {
            list->next->previous=N;
        }

        list->next=N;
    }
}


void create()
{
    int value;
    char ch;
    while(1)
    {
        printf("   \n\tENTER  NUMBER & Character (int,char) (-1 for exit)\n");
        printf("\t");
        scanf("%d",&value);
        if(value==-1)
        {
            display();
            printf("\tNode Create Completed!!");
            MENU();
        }
        scanf(" %c",&ch);


        insert_at_end(value,ch);

    }


}

void delete_item(int value)
{
    node *list = head, *temp=NULL;
    int x = 0;

    while(list!=NULL)
    {
        if(list->a==value)
        {
            if(temp==NULL)
            {
                head = list->next;
                head->previous=NULL;
            }
            else
                temp->next = list->next;


            printf("%d is deleted from list\n", value);
            x = 1;
            free(list);
            break;
        }
        temp = list;
        list = list->next;
        list->previous=temp;
    }
    if(x==0)
        printf("Key not found!\n");
}


int search()
{
    int n;
    printf("   \n\t<<<<<<<<SEARCH VALUE>>>>>>>>\n\n");
    printf("\tENTER ANY VALUE FOR SERACH :");
    scanf("%d",&n);

    node*list=head;
    int x=0;
    while(list!=NULL)
    {
        if(list->a==n)
        {
            printf("\n\t%d is Found\n\n",n);
            x=1;
            break;
        }
        else

            list=list->next;
    }
    if(x==0)
    {
        printf("\n\t%d is  Not Found\n\n",n);
    }
    MENU();
}


void addnode()
{
    int af,y;
    char cf;
    printf("\n\n\n");
    printf("\t1.Insert At First.\n");
    printf("\t2.Insert At LAST.\n");
    printf("\t3.Insert At Nth Position.\n");
    printf("\t4.GO TO MENU\n");
    printf("\n\tChoose Any Option (1-4):");
    int x;

    scanf("%d",&x);
    switch(x)
    {
    case 1:
    {
        printf("\n\t<<<<<<<<Insert At FIRST(int,char)>>>>>>>>\n");

        printf("\t");
        scanf("%d",&af);
        scanf(" %c",&cf);
        insert_at_first(af,cf);
        display();
        addnode();

    }
    case 2:
    {
        printf("\n\t<<<<<<<<Insert At END(int,char)>>>>>>>>\n");


        printf("\t");
        scanf("%d",&af);
        scanf(" %c",&cf);
        insert_at_end(af,cf);
        display();
        addnode();

    }
    case 3:
    {
        printf("\n\t<<<<<<<<Insert At Nth(pos,int,char)>>>>>>>>\n");

        printf("\t");
        scanf("%d",&y);
        scanf("%d",&af);
        scanf(" %c",&cf);
        insert_nth(y,af,cf);
        display();
        addnode();

    }
    case 4:
    {
        MENU();
        break;
    }
    default:
    {
        printf("\tCHOOSE A CORRECT OPTION\n");
        addnode();
    }
    }

}


void delete()
{

    printf("\n\t<<<<<<<<<DELETE NODE>>>>>>>>>\n");
    printf("\t1.Delete By Position \n");
    printf("\t2.Delete By Value \n");
    printf("\t3.GO TO MENU \n\n");
    printf("\tChoose Any Option (1-3):");
    int x,s,l;


    scanf("%d",&x);
    switch(x)
    {
    case 1:
    {
        printf("   \n\t<<<<<<<<DELETE BY POSITION>>>>>>>>\n");
        printf("\t");
        printf("ENTER POSITION:");
        scanf("%d",&s);
        delete_pos(s);
        delete();
    }
    case 2:
    {
        printf("   \n\t<<<<<<<<DELETE BY VALUE>>>>>>>>\n");
        printf("\t");
        printf("ENTER VALUE:");
        scanf("%d",&l);
        delete_item(l);
        delete();
    }
    case 3:
    {
        MENU();
        break;
    }
    default:
    {
        printf("\tCHOOSE A CORRECT OPTION\n");
        delete();
    }
    }


}


void delete_pos(int pos)
{
    node *list=head,*temp=NULL,*tail;


    if(pos==1)
    {
        if(list->next==NULL)
        {
            printf("DATA DELETED\n\n");
            free(list);
        }
        else
        {
            head=list->next;
            head->previous=NULL;
            printf("DATA DELETED\n\n");
            free(list);
        }
    }
    else
    {
        pos=pos-2;
        while(pos!=0 && list->next!=NULL)
        {
            list=list->next;
            pos--;
            if(list==NULL)
            {
                printf("NO DATA FOUND!!\n\n");
                break;
            }
        }
        if(list->next==NULL)
        {
            printf("You Choose Wrong Position!!\n\n");
        }
        else if(list==NULL && pos==0)
        {
            temp=tail;
            tail=temp->previous;
            tail->next=NULL;
            printf("DATA DELETED\n\n");
            free(temp);
        }
        else if(list!=NULL && pos==0)
        {
            temp=list->next;
            temp->next->previous=list;
            list->next=temp->next;
            printf("DATA DELETED\n\n");
            free(temp);
        }
    }
}





void display()
{

    node *list=head;

    if(head==NULL)
    {
        printf("\n\n\tNode is empty!!\n\n");
        printf("\tENTER DATA PLEASE!!\n");
        MENU();

    }
    while(list !=NULL)
    {
        printf("\n\n\tA= %d ,C= %c\n",list->a,list->ch);


        list=list->next;

    }

}


void MENU()
{

    printf("\n\n\t<<<<<<<<<<  WELCOME TO DOUBLY LINK LIST  >>>>>>>>>>>>>\n\n");
    printf("\t1.Create Nodes\n");
    printf("\t2.ADD Nodes\n");
    printf("\t3.Search Nodes\n");
    printf("\t4.DELETE Nodes\n");
    printf("\t5.Display\n");
    printf("\t6.EXIT \n\n\n");

    printf("\tChoose Any Option (1-5):");
    int x;


    scanf("%d",&x);
    switch(x)
    {
    case 1:
    {
        create();
        break;
    }
    case 2:
    {
        addnode();
        break;
    }
    case 3:
    {
        search();
        break;
    }
    case 4:
    {
        delete();
        break;
    }
    case 5:
    {
        dis();
        break;
    }
    case 6:
    {
        break;
    }
    default:
    {
        printf("CHOOSE A CORRECT OPTION\n");
        MENU();
    }
    }
}


void dis()
{

    node *list=head;

    if(head==NULL)
    {
        printf("\n\n\tNode is empty!!\n\n");
        printf("\tENTER DATA PLEASE!!\n");
        MENU();

    }
    while(list !=NULL)
    {
        printf("\n\n\tA= %d ,C= %c\n",list->a,list->ch);


        list=list->next;


    }

    MENU();
}

int main()
{
    head=NULL;
    MENU();


}