CREATE OWN LIBRARY

The program is written here to delete the duplicate elements from the unsorted list. The list is represented here by a singly linked list. The singly linked list can be represented in memory as a user-defined data type i.e. by using ‘structure’ or ‘class’. 

Each node of the linked list contain two parts-

• Data part
• Address part

The structure of the node: 

Let the unsorted list of duplicate elements be:

The two pointers are taken here to delete the duplicate elements from the list. First, one of the pointers will point to the first node of the list. For each node pointed by ‘ptr’, another pointer will be used which will point the node ‘ptr’ and will traverse the rest of the list for finding the duplicate elements.

Now the data of pointer ‘ptr’ will be compared with the data of ‘next[ptr1]’. As they are not the same, ptr1 will be moved to the next node.

Now, the same process will be repeated i.e. the data of ‘ptr’ will be compared with the data of ‘next[ptr1]’. Now, both the data are the same. So, the address of the node pointed by the pointer ‘ptr1’ will be replaced by the address ‘next[next[ptr1]]’.

After deleting the ‘node’ with duplicate data we will get:

Now, the pointer ‘ptr’ will be moved to the next node and the same process will be continued till all the duplicate data of the list are not get deleted.

After deleting all the duplicate elements from the list we will get:

INPUT:  The number of elements to create the list and the elements which are to be inserted
OUTPUT:  a) The list after creating it
	     b) The list after deleting the duplicate elements
PROCESS:
Step 1: Define a structure named ‘node’ which has two parts−
•	The data part of integer type
•	The ‘next’ (points to it’s next node i.e. the address of the next node) part which is a structure(node) type pointer

Step 2: Create a function “void createlist()”
 Step 2.1: Take the number of  elements from user in an ‘integer’ type variable ‘n’
 Step 2.2: For i=0 to (n-1) repeat  Step 2.3 to Step 2.7
 Step 2.3: Take the element which is to be inserted in an integer type variable  ‘x’
 Step 2.4: Create a new node in ‘p’(a ‘node’ type pointer) by using ‘malloc’ function                    
   Set data[p] <-x
 
   Set next[p] <- Null
 Step 2.5: If (head1 = Null) then
   Set head1 <- p
   [End of ‘If’ ]
 Step 2.6: Else   
   Set next[ptr] <- p
   [End of ‘Else’] 

 Step 2.7: Set ptr <- p

[End of  Step 2.2 ‘For’ loop]
[End of  the function “void createlist( )”]   

Step 3: Create a function “void displaylist()”
 Step 3.1: Set p <-head1
 Step 3.2: While(p≠Null) then repeat  Step 3.3 and Step 3.4
 Step 3.3: Print  data[p]
 Step 3.4: Set p<-next[p]	
 [End of  Step 3.2 ‘While’ loop]
 [End of  the function “void displaylist( )”]

Step 4: Create a function “void remove()”
 Step 4.1: Set ptr1 <- head1 
 Step 4.2: while ptr1 ≠ NULL and next[ptr1]≠NULL repeat from step 4.3 to 4.6
 Step 4.3: Set ptr2 <- ptr1 
 Step 4.4: while next[ptr2]≠ NULL repeat step 4.5 
 Step 4.5: if data[ptr1] = data[next[ptr2]] then 
   Set ptr <- next[ptr2] 
   Set next[ptr2] = next[next[ptr2]] 
   Free ptr 
   else 
   Set ptr2 <- next[ptr2] 
 [End of step 4.5 ‘if’]
 [End of step 4.4 ‘while’ loop]
Step 4.6: Set ptr1 <- next[ptr1] 
 [End of step 4.2 ‘while’ loop]
 [End of function ‘remove()’]

Step 5: [Function ‘main()’]
  Call the function ‘createlist()’
  Call the function ‘displaylist()’
  Call the function ‘remove()’
Step 6: Stop.