Doubly Linked List Creation and Insertion At Beg, mid, and at end C++

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#include<bits/stdc++.h>
 using namespace std;
  struct node
  {
      int data;
       struct node *next, *prev;
  };
  struct node *head, *tail, *newnode, *temp;
  int count=0;
  void create()
  {
      int choice=1;
      while(choice==1){
          ::count++;
      newnode = (struct node*)malloc(sizeof(struct node));
      newnode->next=0;
      newnode->prev=0;
      cout<<"\nenter data: ";
      cin>>newnode->data;
      if(head==0)
      {
          head=newnode;
          tail=newnode;
      }
      else
      {
          newnode->prev=tail;
          tail->next=newnode;
          tail=newnode;
      }
      cout<<"Want another element to be inserted(0,1): ";
      cin>>choice;
    }
  }
  void insertbeg()
  {
      int choice = 1;
      while(choice==1){
          ::count++;
      newnode=(struct node*)malloc(sizeof(struct node));
      newnode->next=0;
      newnode->prev=0;
      cout<<"enter data: ";
      cin>>newnode->data;
      //first make the link to the previously existing first node;
      head->prev=newnode;
      newnode->next=head;
      head=newnode;
      cout<<"Want another element to be inserted in beginning(0,1): ";
      cin>>choice;
      }
  }
  void insertend()
  {   int choice =1;
      while(choice==1){
          ::count++;
      newnode=(struct node*)malloc(sizeof(struct node));
      newnode->next=0;
      newnode->prev=0;
      cout<<"enter data: ";
      cin>>newnode->data;
      tail->next=newnode;
      newnode->prev=tail;
      tail=newnode;
      cout<<"Want another element to be inserted at end(0,1): ";
      cin>>choice;
      }
  }
  void insertpos()
  {
      int choice = 1,pos,i;
      while(choice==1)
      {
         cout<<"enter the position of insertion greater than 1 and less than the length of list(0,1): ";
         cin>>pos;
         if(pos>1 && pos<::count)
         {    
            ::count++;
            newnode=(struct node*)malloc(sizeof(struct node));
            newnode->next=0;
            newnode->prev=0;
            cout<<"enter data: ";
            cin>>newnode->data;
            // Forming link;
            temp=head; i=1;
            while(i<pos-1)
            {
                temp=temp->next;
                i++;
            }
            newnode->prev=temp;
            newnode->next=temp->next;
            temp->next->prev=newnode;
            temp->next=newnode;
            cout<<"\nDo you want another element to be inserted in middle (0,1): ";
            cin>>choice;
         }
         else
         {
             cout<<"\nPosition cannot be <=1 or >=size of list\n";
             cout<<"Do you want to insert again(0,1): ";
             cin>>choice;
         }
      }
  }
  void listprint()
  {
      temp=head;
      cout<<"size is: "<<::count<<endl;
      while(temp!=0)
      {
          cout<<temp->data<<" ";
          temp=temp->next;
      }
  }
  int main()
  {
      int f=1, conti=1, choice;
      while(conti==1)
      {
      
      cout<<"\npress 1. to create list";
      cout<<"\npress 2. to enter node at beginning";
      cout<<"\npress 3. to enter node at end";
      cout<<"\npress 4. to enter node at certain position";
      cout<<"\npress 5. to print list";
      cout<<"\nenter your choice from given list: ";
      cin>>choice;
      if(choice==1)
      {   if(f==1)
          {create();
          f=0;}
          else
          cout<<"list already created";
      }
      
      else if(choice==2)
      insertbeg();
      else if(choice==3)
      insertend();
      else if(choice==4)
      insertpos();
      else if(choice==5)
      listprint();
      else
      cout<<"invalid choice";
      
      cout<<"\nDo you want to continue(0,1): ";
      cin>>conti;
      }
  }

Comments

  1. HotTalker30 August 2020 at 23:40

    This is the entire code for doubly linked list creation, insertion,
    You can directly copy entire code and run easily

    ReplyDelete

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