Course on Cyber Security and Ethical Hacking

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M.Tech In Cyber Security

Amrita University is offering M.Tech Programme in Cyber Security.
Check:
http://www.amrita.edu/cyber/

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Program Listings: Linked Lists and Trees

// program for building and printing the elements of the linked list:

# include "stdio.h"
# include "stdlib.h"
struct node
{
int data;
struct node *link;
};
struct node *insert(struct node *p, int n)
{
struct node *temp;
/* if the existing list is empty then insert a new node as the
starting node */
if(p==NULL)
{
p=(struct node *)malloc(sizeof(struct node)); /* creates new node
data value passes
as parameter */

if(p==NULL)
{
printf("Error\n");
exit(0);
}
p-> data = n;
p-> link = p; /* makes the pointer pointing to itself because it
is a circular list*/
}
else
{
temp = p;
/* traverses the existing list to get the pointer to the last node of
it */
while (temp-> link != p)
temp = temp-> link;
temp-> link = (struct node *)malloc(sizeof(struct node)); /*
creates new node using
data value passes as
parameter and puts its
address in the link field
of last node of the
existing list*/
if(temp -> link == NULL)
{
printf("Error\n");
exit(0);
}
temp = temp-> link;
temp-> data = n;
temp-> link = p;
}
return (p);
}
void printlist ( struct node *p )
{
struct node *temp;
temp = p;
printf("The data values in the list are\n");
if(p!= NULL)
{
do
{
printf("%d\t",temp->data);
temp=temp->link;
} while (temp!= p);
}
else
printf("The list is empty\n");
}

void main()
{
int n;
int x;
struct node *start = NULL ;
printf("Enter the nodes to be created \n");
scanf("%d",&n);
while ( n -- > 0 )
{
printf( "Enter the data values to be placed in a node\n");
scanf("%d",&x);
start = insert ( start, x );
}
printf("The created list is\n");
printlist ( start );
}

//program for deleting a specified node from a singly linked list
# include "stdio.h"
# include "stdlib.h"
struct node *delet ( struct node *, int );
int length ( struct node * );
struct node
{
int data;
struct node *link;
};
struct node *insert(struct node *p, int n)
{
struct node *temp;
if(p==NULL)
{
p=(struct node *)malloc(sizeof(struct node));
if(p==NULL)
{
printf("Error\n");
exit(0);
}
p-> data = n;
p-> link = NULL;
}
else
{
temp = p;
while (temp-> link != NULL)
temp = temp-> link;
temp-> link = (struct node *)malloc(sizeof(struct node));
if(temp -> link == NULL)
{
printf("Error\n");
exit(0);
}
temp = temp-> link;
temp-> data = n;
temp-> link = NULL;
}
return (p);
}

void printlist ( struct node *p )
{
printf("The data values in the list are\n");
while (p!= NULL)
{
printf("%d\t",p-> data);
p = p-> link;
}
}

void main()
{
int n;
int x;
struct node *start = NULL;
printf("Enter the nodes to be created \n");
scanf("%d",&n);
while ( n- > 0 )
{
printf( "Enter the data values to be placed in a node\n");
scanf("%d",&x);
start = insert ( start, x );
}
printf(" The list before deletion id\n");
printlist ( start );
printf("% \n Enter the node no \n");
scanf ( " %d",&n);
start = delet (start , n );
printf(" The list after deletion is\n");
printlist ( start );
}

/* a function to delete the specified node*/
struct node *delet ( struct node *p, int node_no )
{

struct node *prev, *curr ;
int i;

if (p == NULL )
{
printf("There is no node to be deleted \n");
}
else
{
if ( node_no > length (p))
{
printf("Error\n");
}
else
{
prev = NULL;
curr = p;
i = 1 ;
while ( i < node_no )
{
prev = curr;
curr = curr-> link;
i = i+1;
}
if ( prev == NULL )
{
p = curr -> link;
free ( curr );
}
else
{
prev -> link = curr -> link ;
free ( curr );
}
}
}
return(p);
}
/* a function to compute the length of a linked list */
int length ( struct node *p )
{
int count = 0 ;
while ( p != NULL )
{
count++;
p = p->link;
}
return ( count ) ;
}

//program to insert a node at the specified position
# include "stdio.h"
# include "stdlib.h"
int length ( struct node * );
struct node
{
int data;
struct node *link;
};

/* a function which appends a new node to an existing list used for
building a list */
struct node *insert(struct node *p, int n)
{
struct node *temp;
if(p==NULL)
{
p=(struct node *)malloc(sizeof(struct node));
if(p==NULL)
{
printf("Error\n");
exit(0);
}
p-> data = n;
p-> link = NULL;
}
else
{
temp = p;
while (temp-> link != NULL)
temp = temp-> link;
temp-> link = (struct node *)malloc(sizeof(struct node));
if(temp -> link == NULL)
{
printf("Error\n");
exit(0);
}
temp = temp-> link;
temp-> data = n;
temp-> link= NULL;
}
return (p);
}
/* a function which inserts a newly created node after the specified
node */
struct node * newinsert ( struct node *p, int node_no, int value )
{
struct node *temp, * temp1;
int i;
if ( node_no <= 0 || node_no > length (p))
{
printf("Error! the specified node does not exist\n");
exit(0);
}
if ( node_no == 0)
{
temp = ( struct node * )malloc ( sizeof ( struct node ));
if ( temp == NULL )
{
printf( " Cannot allocate \n");
exit (0);
}
temp -> data = value;
temp -> link = p;
p = temp ;
}
else
{
temp = p ;
i = 1;
while ( i < node_no )
{
i = i+1;
temp = temp-> link ;
}
temp1 = ( struct node * )malloc ( sizeof(struct node));
if ( temp == NULL )
{
printf ("Cannot allocate \n");
exit(0)
}
temp1 -> data = value ;
temp1 -> link = temp -> link;
temp -> link = temp1;
}
return (p);
}

void printlist ( struct node *p )
{
printf("The data values in the list are\n");
while (p!= NULL)
{
printf("%d\t",p-> data);
p = p-> link;
}
}
void main ()
{
int n;
int x;
struct node *start = NULL;
printf("Enter the nodes to be created \n");
scanf("%d",&n);
while ( n- > 0 )
{
printf( "Enter the data values to be placed in a node\n");
scanf("%d",&x);
start = insert ( start, x );
}
printf(" The list before deletion is\n");
printlist ( start );
printf(" \n Enter the node no after which the insertion is to be
done\n");
scanf ( " %d",&n);
printf("Enter the value of the node\n");
scanf("%d",&x);
start = newinsert(start,n,x);
printf("The list after insertion is \n");
printlist(start);
}

//program for building and printing the elements of the circular linked list

# include "stdio.h"
# include "stdlib.h"
struct node
{
int data;
struct node *link;
};
struct node *insert(struct node *p, int n)
{
struct node *temp;
/* if the existing list is empty then insert a new node as the
starting node */
if(p==NULL)
{
p=(struct node *)malloc(sizeof(struct node)); /* creates new
node data value passes
as parameter */
if(p==NULL)
{
printf("Error\n");
exit(0);
}
p-> data = n;
p-> link = p; /* makes the pointer pointing to itself because it
is a circular list*/
}
else
{
temp = p;
/* traverses the existing list to get the pointer to the last node of
it */
while (temp-> link != p)
temp = temp-> link;
temp-> link = (struct node *)malloc(sizeof(struct node)); /*
creates new node using
data value passes as
parameter and puts its
address in the link field
of last node of the
existing list*/
if(temp -> link == NULL)
{
printf("Error\n");
}
exit(0);
temp = temp-> link;
temp-> data = n;
temp-> link = p;
}
return (p);
}
void printlist ( struct node *p )
{
struct node *temp;
temp = p;
printf("The data values in the list are\n");
if(p!= NULL)
{
do
{
printf(%d\t",temp->data);
temp=temp->link;
} while (temp!= p)
}
else
printf("The list is empty\n");
}

void main()
{
int n;
int x;
struct node *start = NULL ;
printf("Enter the nodes to be created \n");
scanf("%d",&n);
while ( n- > 0 )
{
printf( "Enter the data values to be placed in a
node\n");
scanf("%d",&x);
start = insert ( start, x );
}
printf("The created list is\n");
printlist ( start );
}

// program for building and printing the elements of a doubly linked list

# include "stdio.h"
# include "stdlib.h"
struct dnode
{
int data;
struct dnode *left, *right;
};
struct dnode *insert(struct dnode *p, struct dnode **q, int n)
{
struct dnode *temp;
/* if the existing list is empty then insert a new node as the
starting node */
if(p==NULL)
{
p=(struct dnode *)malloc(sizeof(struct dnode)); /* creates new
node data value
passed as parameter */

if(p==NULL)
{
printf("Error\n");
exit(0);
}
p->data = n;
p-> left = p->right =NULL;
*q =p;
}
else
{
temp = (struct dnode *)malloc(sizeof(struct dnode)); /* creates
new node using
data value passed as
parameter and puts its
address in the temp
*/
if(temp == NULL)
{
printf("Error\n");
exit(0);
}
temp->data = n;
temp->left = (*q);
temp->right = NULL;
(*q)->right = temp;
(*q) = temp;
}
return (p);
}
void printfor( struct dnode *p )
{
printf("The data values in the list in the forward order are:\n");
while (p!= NULL)
{
printf("%d\t",p-> data);
p = p->right;
}
}
void printrev( struct dnode *p )
{
printf("The data values in the list in the reverse order are:\n");
while (p!= NULL)
{
printf("%d\t",p->data);
p = p->left;
}
}
void main()
{
int n;
int x;
struct dnode *start = NULL ;
struct dnode *end = NULL;
printf("Enter the nodes to be created \n");
scanf("%d",&n);
while ( n-- > 0 )
{
printf( "Enter the data values to be placed in a node\n");
scanf("%d",&x);
start = insert ( start, &end,x );
}
printf("The created list is\n");
printfor ( start );
printrev(end);
}

//program to create a binary search tree
#include "stdio.h"
#include "stdlib.h"
struct tnode
{
int data;
struct tnode *lchild, *rchild;
};

struct tnode *insert(struct tnode *p,int val)
{
struct tnode *temp1,*temp2;
if(p == NULL)
{
p = (struct tnode *) malloc(sizeof(struct tnode)); /* insert the new node as root node*/
if(p == NULL)
{
printf("Cannot allocate\n");
exit(0);
}
p->data = val;
p->lchild=p->rchild=NULL;
}
else
{
temp1 = p;
/* traverse the tree to get a pointer to that node whose child will be the newly created node*/
while(temp1 != NULL)
{
temp2 = temp1;
if( temp1 ->data > val)
temp1 = temp1->lchild;
else
temp1 = temp1->rchild;
}
if( temp2->data > val)
{
temp2->lchild = (struct tnode*)malloc(sizeof(struct tnode));/*inserts the newly created node as left child*/
temp2 = temp2->lchild;
if(temp2 == NULL)
{
printf("Cannot allocate\n");
exit(0);
}
temp2->data = val;
temp2->lchild=temp2->rchild = NULL;
}
else
{
temp2->rchild = (struct tnode*)malloc(sizeof(struct tnode));/ *inserts the newly created node
as left child*/
temp2 = temp2->rchild;
if(temp2 == NULL)
{
printf("Cannot allocate\n");
exit(0);
}
temp2->data = val;
temp2->lchild=temp2->rchild = NULL;
}
}
return(p);
}
/* a function to binary tree in inorder */
void inorder(struct tnode *p)
{
if(p != NULL)
{
inorder(p->lchild);
printf("%d\t",p->data);
inorder(p->rchild);
}
}
void main()
{
struct tnode *root = NULL;
int n,x;
printf("Enter the number of nodes\n");
scanf("%d",&n);
while( n - > 0)
{
printf("Enter the data value\n");
scanf("%d",&x);
root = insert(root,x);
}
inorder(root);
}

//program to find a key in a binary search tree
#include "stdio.h"
#include "stdlib.h"
struct tnode
{
int data;
struct tnode *lchild, *rchild;
};
/* A function to serch for a given data value in a binary search tree*/
struct tnode *search( struct tnode *p,int key)
{
struct tnode *temp;
temp = p;
while( temp != NULL)
{
if(temp->data == key)
return(temp);
else
if(temp->data > key)
temp = temp->lchild;
else
temp = temp->rchild;
}
return(NULL);
}

/*an iterative function to print the binary tree in inorder*/
void inorder1(struct tnode *p)
{
struct tnode *stack[100];
int top;
top = −1;
if(p != NULL)
{
top++;
stack[top] = p;
p = p->lchild;
while(top >= 0)
{
while ( p!= NULL)/* push the left child onto stack*/
{
top++;
stack[top] =p;
p = p->lchild;
}
p = stack[top];
top-;
printf("%d\t",p->data);
p = p->rchild;


if ( p != NULL) /* push right child*/
{
top++;
stack[top] = p;
p = p->lchild;
}

}
}
}
/* A function to insert a new node in binary search tree to
get a tree created*/
struct tnode *insert(struct tnode *p,int val)
{
struct tnode *temp1,*temp2;
if(p == NULL)
{
p = (struct tnode *) malloc(sizeof(struct tnode)); /* insert the new node as root node*/
if(p == NULL)
{
printf("Cannot allocate\n");
exit(0);
}
p->data = val;
p->lchild=p->rchild=NULL;
}
else
{
temp1 = p;
/* traverse the tree to get a pointer to that node whose child will be the newly created node*/
while(temp1 != NULL)
{
temp2 = temp1;
if( temp1 ->data > val)
temp1 = temp1->lchild;
else
temp1 = temp1->rchild;
}
if( temp2->data > val)
{
temp2->lchild = (struct tnode*)malloc(sizeof(struct tnode));/ *inserts the newly created node
as left child*/
temp2 = temp2->lchild;
if(temp2 == NULL)
{
printf("Cannot allocate\n");
exit(0);
}
temp2->data = val;
temp2->lchild=temp2->rchild = NULL;
}
else
{
temp2->rchild = (struct tnode*)malloc(sizeof(struct tnode));/ *inserts the newly created node
as left child*/
temp2 = temp2->rchild;
if(temp2 == NULL)
{
printf("Cannot allocate\n");
exit(0);
}
temp2->data = val;
temp2->lchild=temp2->rchild = NULL;
}
}
return(p);
}
void main()
{
struct tnode *root = NULL, *temp = NULL;
int n,x;
printf("Enter the number of nodes in the tree\n");
scanf("%d",&n);
while( n - > 0)
{
printf("Enter the data value\n");
scanf("%d",&x);
root = insert(root,x);
}
printf("The created tree is :\n");
inorder1(root);
printf("\n Enter the value of the node to be searched\n");
scanf("%d",&n);
temp=search(root,n);
if(temp != NULL)
printf("The data value is present in the tree \n");
else
printf("The data value is not present in the tree \n");
}