File Structure ( FS ) Lab Program 10 ( 6th Semester Information Science)

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Program 10 : Write a C++ program to implement B-Tree for a given set of integers and its operations insert ( ) and search ( ). Display the tree.

#include<iostream>
#include<cmath>

using namespace std;

struct node{
int ele[4];
int child[4];
node *next;
};

class bptree{
public:
node *tree[10][10];
int count[10];
int leaf;
int path[10];
node *head;

bptree();
node* create_node();
void insert(int);
void main_search(int);
void display_tree();
void insert_node(node,int);
void search(int);
int search_node(node,int);
int nodefull(node);
void split(node);
};

bptree::bptree()
{
leaf=-1;
for(int i=0;i<10;i++)
{
count[i]=-1;
path[i]=-1;
}
}

node* bptree::create_node()
{
node* n;
n=new node;
for(int i=0;i<4;i++)
{
n->ele[i]=-1;
n->child[i]=-1;
}
n->next=NULL;
return n;
}

void bptree::insert(int key)
{
int n,parent;
node *first_node;
if(leaf==-1)
{
first_node=create_node();
tree[0][0]=first_node;
leaf++;
count[0]++;
first_node->ele[0]=key;
head=first_node;
}
else if(leaf==0)
{
if(nodefull(tree[0][0]))
{
path[leaf]=0;
split(tree[0][0]);
insert(key);
}
else
insert_node(tree[0][0],key);
}
else
{
search(key);
n=path[leaf];
parent=path[leaf-1];
if((nodefull(tree[leaf][n])))
{
split(tree[leaf][n]);
insert(key);
}
else
insert_node(tree[leaf][n],key);
}
}

void bptree::main_search(int key)
{
int flag=0,i;
node *node1;
search(key);
node1=tree[leaf][path[leaf]];
for(i=0;node1->ele[i]!=-1;i++)
if(node1->ele[i]==key)
{
flag=1;
break;
}
cout<<“n The path traversed is:”;
for(i=0;path[i]!=-1;i++)
cout<<path[i]<<“->”;
if(flag)
cout<<“nnElement found”;
else
cout<<“nnNot Found”;
}

void bptree::display_tree()
{
int i,j,k;
for(i=0;i<=leaf;i++)
{
cout<<“nnLevel——“<<i<<“n”;
for(j=0;j<=count[i];j++)
{
if(i!=leaf) k=1;
else         k=0;
for(;tree[i][j]->ele[k]!=-1;k++)
cout<<”  “<<tree[i][j]->ele[k]<<“t”;
}
}
}

void bptree::search(int key)
{
int i,j,temp;
path[0]=0;
if(leaf)
{
j=0;
for(i=0;i<leaf;i++)
{
temp=search_node(tree[i][j],key);
path[i+1]=temp;
j=temp;
}
}
}

int bptree::search_node(node *node1,int key)
{
if(key<=node1->ele[0])
return node1->child[0];
for(int i=1;i<4;i++)
{
if((key>=node1->ele[i]) && (key<node1->ele[i+1]))
return node1->child[i];
else if(node1->ele[i+1]==-1)
return node1->child[i];
}
}

int bptree::nodefull(node* node1)
{
if(node1->ele[3]!=-1)return 1;
else     return 0;
}

void bptree::insert_node(node node1,int key)
{
int flag=0,count=-1,i,j,x,y,l;
node *newnode,parent;
for(i=0;i<4;i++)
if(node1->ele[i]!=-1)
++count;
i=0;
while(!flag&&node1->ele[i]!=-1)
{
if(node1->ele[i]>key)
{
flag=1;
for(int j=count;j>=i;j–)
node1->ele[j+1]=node1->ele[j];
node1->ele[i]=key;
}
i++;
}
if(!flag)
node1->ele[count+1]=key;
if(node1->ele[0]==key)
{
for(i=leaf-1;i>=0;i–)
{
x=path[i+1];
if(tree[i][path[i]]->ele[x]>key)
tree[i][path[i]]->ele[x]=key;
else
insert_node(tree[i][x],key);
}
}

for(i=0;i<=count+1;i++)
cout<<“tt”<<node1->ele[i];
}

void bptree::split(node oldnode)
{
node *newnode,parent,n1,n2;
int i,j,k,n,t,x,y,pos;
newnode=create_node();
newnode->ele[0]=oldnode->ele[2];
newnode->ele[1]=oldnode->ele[3];
oldnode->ele[2]=-1;
oldnode->ele[3]=-1;
t=count[leaf];
n=path[leaf];
for(i=t,j=t+1;i>n;i–,j–)
tree[leaf][j]=tree[leaf][i];
newnode->next=tree[leaf][n]->next;
tree[leaf][n]->next=newnode;
tree[leaf][n+1]=newnode;
count[leaf]++;
x=leaf;
if(count[leaf]+1==1) t=1;
else
t=log(count[leaf]+1)/log(2);
if(t!=leaf)
{
++leaf;
count[leaf]=count[x];
for(i=0;i<=count[leaf];i++)
std::swap(tree[leaf][i],tree[x][i]);
}
for(i=leaf-1;i>=0;i–) count[i]=-1;
for(i=t,j=i-1;i>0;i–,j–)
{
for(k=0;k<=(count[i])/3;k++)
{
n1=tree[i][2k];
n2=tree[i][(2k)+1];

newnode=create_node();
count[j]++;
tree[j][count[j]]=newnode;
newnode->ele[0]=n1->ele[0];
newnode->child[0]=2k;
newnode->ele[1]=n2->ele[0];
newnode->child[1]=(2k)+1;
}
if(count[i]!=1 && count[i]%2==0)
{
n2=tree[i][count[i]];
for(y=0;n2->ele[y]!=-1;y++);
newnode->ele[2]=n2->ele[0];
newnode->child[2]=count[i];
}
}
}
int main()
{
bptree bt;
int choice,key;
while(1)
{
cout<<“nnnMain Menun———–n1:Insertn2:Searchn3:Display treen4:ExitnnEnter your choice :”;
cin>>choice;
switch(choice)
{
case 1:cout<<“nnEnter the element: “;
cin>>key;
bt.insert(key);
break;
case 2: cout<<“nEnter the key: “;
cin>>key;
bt.main_search(key);
break;
case 3: bt.display_tree();
break;
case 4: return 0;
default: cout<<“nnEnter valid Choice”;
}
}
}