Skip to main content

Doubly Link List

Doubly Link List is data structure which contains list of node having info part and pointer to previous and next node of the list. This makes traversal easy. The last node's next and first node's prev pointer points to nothing. Before going to discuss the operation on doubly link list, we will first see the basic structure of the data type and see how it could be represented in c programming. First we will see the how the node of doubly link list is represented. See the image below:
The component of singly list node:
  • info : It contains the actual information
  • next : This field points to the next node in the list
  • prev : This field points to the previous node in the list
Now we see how the doubly link list is represented. See the image below:



The component of doubly list are:
  • START pointer points to the first node of the list
  • NODE : Each node have info field, next pointer to point next NODE in the list and prev pointer to point previous node in the list
  • prev of first node and next of last node will points to NULL
The above structure of node is represented as below:

struct node{
 int info;
 struct node *next, *prev;
};
typedef struct node NODE;

Now we see the different operation that can be performed on the doubly link list:
Labels:

Comments

Post a Comment

Popular posts from this blog

Prefix to Infix Conversion

With a given Prefix Expression, we will see how to convert Prefix Expression into Infix Expression using stack.   Algorithm to convert Prefix Expression to Infix Expression: In this algorithm, we will use stack to store operands during the conversion. The step are as follows: Read the prefix string While the end of prefix string scanned from right to left symb = the current character If symb is an operator poped_sym1 = pop the stack poped_sym2 = pop the stack concat the string  STR = ( poped_sym1 )+ ( operator )+( poped_sym2 ) push the string STR into stack Else push the operand symb into stack End If End While infix_str = pop the stack   Function to convert Prefix Expression to Infix Expression: void prefix_to_infix(char prefix[], char infix[]){ char op[2]; //operator string char poped1[MAX]; char poped2[MAX]; char temp[MAX]; int i = strlen(prefix); op[1] = '\0'; while(--i != -1){ if(prefix[i] == ' '){ continue; } if(isoper...
Post a Comment
Read more

Concatenating two link list

Here we will see how to concat two single link list into other link list. First we copy the content of first list in third list and then the content of second list into third list. Algorithm for concatenation of two link list: This algorithm will use three list. List 1 and List 2 will be concatenated into List 3. The step below: Copy the list 1 into list 3 Copy the list 2 at the last of list 3 Function to concat two link list: void concatLists(NODE **start1, NODE **start2, NODE **mergeinto){ NODE *temp; temp = *start1; while(temp != NULL){ insertAtLast(&*mergeinto, temp->info); temp = temp->next; } temp = *start2; while(temp != NULL){ insertAtLast(&*mergeinto, temp->info); temp = temp->next; } }   Program to concat two link lists: #include <stdio.h> #include <malloc.h> struct node{ int info; struct node *next; }; typedef struct node NODE; void insertAtLast(NODE **, int); void traverse(NODE **); void concatLists(NODE **,...
Post a Comment
Read more

Implementation of Stack to store different data types

Here we will see how to implement stack using structure and union to store different datatypes in stack. First we define the basic structure for elements/items to be stored in the stack. struct Items{ int ele_type; union { int ivalue; float fvalue; char *strvalue; } stack_element; }; In the above code, we have defined a Items structure to store the info about the type of items in ele_type variable and a union variable named stack_element to store the actual value of stack items. In union the, ivalue is used to store the integer value, fvalue to store floating value and strvalue to store the string value. If you wish to add other datatype, you can add any datatype within the union. Now we will define the structure to implement the stack. The code below: struct Stack{ int top; struct Items element[MAX]; }; In the above code, struct Stack is defined to hold the top of stack and the array of Items structure named element to hold the actual Items defined above. MA...
Post a Comment
Read more