Page 110 - DCAP407_DATA_STRUCTURE

Unit 6: Linked List Operations

4. The switch statement is used to implement the three operations. The details
of the actions performed in each switch case is as follows:
(a) Case 1 and case 2 call the function display() to display the elements
present in a list or to display a message “linked list is empty” in case
there are no elements.
(b) Case 3 prompts the input from the user to insert a new node at the
beginning of the list by calling insert_beg() function and also calls the
display() function to display the list.
(c) Case 4 results in the exit of the program.
(d) The default prints a message “your choice is wrong” in case the user
enters input greater than 4.
5. The program terminates when the user enters 4.

6.3.2 Inserting a Node after a Given Node
Let us consider START as the initial position in a list, data as the input entered by a user, pos as any
position in the list where the data will be inserted, and q and temp as the temporary pointers to hold
the node address.
Algorithm to insert a new node after a given node is as follows:
1. Input the data

2. Specify the pos where the data is to be inserted
3. Initialize q to START.
4. If q is equal to NULL, then print “there are less elements present in the list than the entered
position number”
5. for (i=0;i<pos-1;i++). q=q->link;

temp=(struct node*)malloc(sizeof (struct node));
temp->link=q->link;
temp->value=data;
q->link=temp;
6. Repeat step 5 until i value is not less than pos-1
7. Exit.

The following program inserts a node after a given node:

#include<stdio.h>
#include<conio.h>
#include<malloc.h>
#include<process.h>

void createlist(int);
void add_beginning(int);
void add_after(int, int);
void Display();
struct node
{
int value;
struct node *link;
}*START;

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