115 lines
2.2 KiB
C
115 lines
2.2 KiB
C
#include <stdio.h>
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#include <stdlib.h>
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typedef struct cnode *cnptr;
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typedef struct cnode
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{
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int data;
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cnptr next;
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cnptr prev;
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}cnode;
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cnptr last=NULL;
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cnptr createCnode(int val)
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{
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cnptr temp=(cnptr)malloc(sizeof(cnode));
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temp->data=val;
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temp->next=NULL;
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temp->prev=NULL;
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return temp;
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}
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void insertBegin(int val)
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{
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cnptr temp=createCnode(val);
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if(last==NULL)
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{
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last=temp;
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last->next=last;
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last->prev=last;
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}
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else
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{
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temp->next=last->next;//head
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last->next->prev=temp;
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temp->prev=last;
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last->next=temp;
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}
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}
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void deleteend()
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{
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cnptr current;
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if(last==NULL)
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{
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printf("List is empty");
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}
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else
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{
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cnptr previous=last->prev;
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previous->next=last->next;
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last->next->prev=previous;
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free(last);
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last=previous;
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}
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}
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void revtraverse()
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{
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cnptr current=last;
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printf("%d ",current->data);
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current=current->prev;
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while(current!=last)
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{
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printf("%d ",current->data);
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current=current->prev;
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}
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printf("\n");
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}
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void traverse()
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{
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cnptr current=last;
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current=current->next;
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while(current!=last)
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{
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printf("%d ",current->data);
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current=current->next;
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}
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printf("%d\n",current->data);
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}
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int main()
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{
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char contin='y';
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int choice;
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while(contin=='y')
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{
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printf("What do you want to do? \n 1. For inserting at beginning \n 2. For deleting at the end. \n 3. For traversing the doubly LL\n");
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scanf("%d",&choice);
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switch(choice)
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{
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case 1:
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{
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int val;
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printf("Enter the value\n");
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scanf("%d",&val);
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insertBegin(val);
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break;
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}
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case 2:
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{
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deleteend();
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printf("Element deleted\n");
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break;
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}
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case 3:
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{
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printf("elements of the list are\n");
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traverse();
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break;
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}
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}
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printf("continue?(y/n)\n");
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fflush(stdin);
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scanf("%c",&contin);
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}
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}
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