Character stuffing done using linked list concept

linkedcharacterstuff.c

@@ -0,0 +1,115 @@
+#include<stdio.h>
+#include<string.h> //for string length
+#include<stdlib.h> //for malloc function
+
+//define structure of the node
+struct node{
+	char c;
+	struct node *next;
+
+};
+
+int main()
+{   
+    int count,length,i;
+	struct node* head =NULL;
+	struct node* tail = NULL;
+
+    char p[50];
+	printf("\n Enter a string : ");
+	scanf("%s",p);
+    length = strlen(p);
+
+    //define a # node for stuffing it at the beginning of the string
+    struct node* temp1 = (struct node *)malloc(sizeof(struct node));
+	temp1->c = '#';
+	temp1->next = NULL;
+	head = temp1; // initialise head and tail to it
+    tail=temp1;
+
+
+    i=0;
+	while(i < length)
+	{
+
+			struct node *temp = (struct node *)malloc(sizeof(struct node));
+            tail->next = temp;
+            temp->c = p[i];
+            temp->next = NULL;
+			tail = temp;
+	        i++;
+
+	}
+
+    //define a # node for stuffing it at the ending of the string
+	struct node *temp2 = (struct node *)malloc(sizeof(struct node));
+	temp2->c = '#';
+	temp2->next = NULL;
+	tail->next = temp2;
+	tail=temp2;
+
+
+    // now we will stuff $ infront of $ or # tht might be present in the data
+	struct node *train, *prev;
+	train= head;
+    prev = head;
+   //first traverse the first node then we will cross the first # 
+	train = train->next;
+    count = 1 ; //since first node is traversed we add 1 to count
+
+	while(train->next != NULL)
+	{  
+		if(train->c == '$' || train->c == '#' )
+			{
+				struct node* insert = (struct node * )malloc(sizeof(struct node));
+				insert->c = '$';
+                prev->next = insert;
+                insert->next = train;
+                prev = insert;
+                train = train->next;
+                prev = prev->next;
+				count += 2; // if $ or  # we insert another $ before it so count is increased by 2
+
+			}
+
+		else
+            {   prev = prev->next;
+                train = train->next;
+                count += 1;
+
+            }
+
+
+		}
+
+    printf("\n Before the packet is handed over to data link layer the data is : ");
+     printf("%s",p);
+
+	printf("\n After the packet is handed over to data link layer the data is stuffed as : ");
+    struct node* printit;
+    printit = head;
+    i = 0;
+    	while(i <= count)
+	{   
+	        printf("%c",printit->c);
+            printit = printit->next;
+             	i++;
+    }
+
+    // free all the nodes
+    struct node * freeit;
+    freeit = head;
+    while(head != NULL)
+    {
+        head = head->next;
+        free(freeit);
+        freeit = head;
+
+    }
+    free(head);
+
+
+return 0;	
+
+
+}