Tree traversal (preorder,inorder,postorder) using linklist (c++)

#include<iostream>
using namespace std;

struct node
{
    int data;
    struct node *left;
    struct node *right;
};

/**********Element insertion*****************/

node* insert(node *root,int data)
{
    if(root==NULL)
    {
        root=new node();
        root->data=data;
        root->left=root->right=NULL;
    }
    else if(data<=root->data)
    {
        root->left=insert(root->left,data);
    }
    else
    {
        root->right=insert(root->right,data);
    }
    return root;
}

/*************Printing in preorder*************/

void preorder(node *root)
{
    if(root==NULL)
    return;

    cout<<" "<<root->data;
    preorder(root->left);
    preorder(root->right);
}

/**************printing in inorder************/

void inorder(node *root)
{
    if(root==NULL)
    return;

    inorder(root->left);
    cout<<" "<<root->data;
    inorder(root->right);
}

/**********printing in postorder************/

void postorder(node *root)
{
    if(root==NULL)
    return;
    postorder(root->left);
    postorder(root->right);
    cout<<" "<<root->data;

}

/**************Driver Function***********/
int main()
{
    node *root=NULL;

    root=insert(root,10);
    root=insert(root,20);
    root=insert(root,30);
    root=insert(root,15);
    root=insert(root,9);
    root=insert(root,25);


    cout<<"\n preorder"<<endl;
    preorder(root);
    cout<<"\n Inorder"<<endl;
    inorder(root);
    cout<<"\n Postorder"<<endl;
    postorder(root);
    cout<<endl;


    return 0;
}

output:

Read More

Implementation of queue using linklist (C++)

#include<iostream>
using namespace std;

struct queue
{
    int data;
    struct queue *next;
};

 queue *front=NULL;
 queue *rear=NULL;
    int count=0;
/**********Inserting Element in Queue******************/
void enqueue(int x)
{
  queue *temp;
  temp=new queue();
  temp->data=x;
  temp->next=NULL;
  if(front==NULL && rear==NULL)
  {
      front=rear=temp;
      count++;
  }
  else
  {
      rear->next=temp;
      rear=temp;
      count++;
  }
}
/*********displaying elements in Queue********************/

void display(int count)
{
    queue *temp;
    temp=front;
    for(int i=0;i<count;i++)
    {
        cout<<temp->data<<" ";
        temp=temp->next;
    }
}
/*******Removing element from Queue*********************/

void dequeue()
{
    if(front==NULL)
    {
        cout<<"Queue is empty"<<endl;
    }
    else
    {
        queue *temp;
        temp=front;
        front=front->next;
        delete temp;
        count--;

        cout<<" \n Item Dequeued Successfully"<<endl;
    }
}

/****************Driver Function************************/

int main()
{
    int choice;
    int x;
    do
    {
        cout<<"Enter element is Queue :"<<endl;
        cin>>x;
        enqueue(x);


    cout<<"Do you want to enQueue again?"<<endl;
    cin>>choice;
    }while(choice==1);

    cout<<"After Enqueue"<<endl;
    display(count);

    do
    {
    dequeue();
    cout<<"Do you want to DeQueue again?"<<endl;
    cin>>choice;
    }while(choice==1);

    cout<<"After dequeue"<<endl;
    display(count);

    return 0;

}

Read More

Circular queue using array(insertion, deletion)

#include <iostream>

using namespace std;

int Q[10];

int size=10;

int count=0;

int rear=0;

int front=0;

void enQ(int element)

{

   if(count==size)

   {

       cout<<"Queue Overflow"<<endl;

   }

   else

   {

       Q[rear]=element;

       rear=(rear+1)%size;

       count++;

   }

}

void DeQ()

{

    if(count==0)

    {

        cout<<"Under Flow"<<endl;

    }

    else

    {

        Q[front]=0;

        front=(front+1)%size;

        count--;

    }

}

bool isempty()

{

    if(count==0)

    {

        return true;

    }

}

int main()

{

    int element;

    int e;

    if(isempty()==true)

    {

        cout<<"Queue is empty"<<endl;

    }

    /*************Enqueue*************/

    do

    {

    cout<<"Enter element in queue:"<<endl;

    cin>>element;

    enQ(element);

    cout<<"Do you want enqueue again?" <<endl;

    cin>>e;

    }while(e==1);

    /************display*************/

    cout<<"After inserting value in circular queue"<<endl;

    for(int i=front;i<=count;i++)

    {

        cout<<Q[i]<<" ";

    }

    /***************deletion***************/

    int d;

    cout<<"Do you want to delete from the queue(1=y): "<<endl;

    cin>>d;

    if(d==1)

    {

        int c;

        do

        {

        DeQ();

        cout<<"DO you want to enqueue again?(1=y)"<<endl;

        cin>>c;

        }while(c==1);

    }

    /************display*************/

    cout<<"After Dequeuing"<<endl;

    for(int i=front;i<=count;i++)

    {

        cout<<Q[i]<<" ";

    }

    return 0;

}

Read More

Doubly Linklist (insertion,deletion of a node)

#include <iostream>
using namespace std;
struct node2
{
    int data2;
    struct node2 *previous;
    struct node2 *next2;
};
int main()
{
    node2 *head2;
    node2 *last2;
    node2 *temp2;
    last2=0;
    int choice;
    do
    {
    cout<<"Enter data in Doubly node:"<<endl;
    temp2=new node2();
    cin>>temp2->data2;
    if(last2==0)
    {
        temp2->next2=0;
        temp2->previous=0;
        last2=head2=temp2;
    }
    else
    {
        temp2->next2=0;
        temp2->previous=last2;
        last2->next2=temp2;
        last2=temp2;
    }
    cout<<"\nDo you want to create a new node (1=yes,0=NO): ";
    cin>>choice;
    }while(choice==1);
    cout<<"Printing from start"<<endl;
    temp2=head2;
    while(temp2!=0)
    {
      cout<<temp2->data2<<" ";
     temp2=temp2->next2;
    }
    cout<<"\n Printing from end"<<endl;
    temp2=last2;
    while(temp2!=0)
    {
      cout<<temp2->data2<<" ";
     temp2=temp2->previous;
    }
   /******************************************/
       do
    {
    cout<<"Enter data"<<endl;
    temp2=new node2();
    cin>>temp2->data2;
    if(last2==0)
    {
        temp2->next2=0;
        temp2->previous=0;
        last2=head2=temp2;
    }
    else
    {
        temp2->next2=head2;
        temp2->previous=0;
        head2->previous=temp2;
        head2=temp2;
    }
    cout<<"\nDo you want to create a new node (1=yes,0=NO): ";
    cin>>choice;
    }while(choice==1);
    cout<<"\n Printing from start"<<endl;
    temp2=head2;
    while(temp2!=0)
    {
      cout<<temp2->data2<<" ";
     temp2=temp2->next2;
    }
    return 0;
}

Read More