Tuesday, 20 October 2026
Sunday, 18 October 2026
Circular queue
#include <iostream>
using namespace std;
int main()
{
int q[5], front = -1, rear = -1;
int choice, value, i;
do
{
cout << "\n1. Insert";
cout << "\n2. Delete";
cout << "\n3. Display";
cout << "\n4. Exit";
cout << "\nEnter choice: ";
cin >> choice;
switch (choice)
{
case 1:
if ((rear + 1) % 5 == front)
cout << "Queue is Full";
For example, if rear = 4 and front = 0:
[ (4+1)%5=0 ]
Since 0 == front, the queue is full.
else
{
cout << "Enter value: ";
cin >> value;
if (front == -1)
front = 0;
If the queue is empty, front is set to 0 because the first element is being inserted.
rear = (rear + 1) % 5;
q[rear] = value;
}
rear = (rear + 1) % 5; moves rear to the next position.
q[rear] = value; stores the value at that position.
Example: If rear = -1, then:[ (-1+1)%5=0 ]
Therefore, rear = 0, and the value is stored at q[0].
break;
case 2:
if (front == -1)
cout << "Queue is Empty";
else
{
cout << "Deleted: " << q[front];
if (front == rear)
front = rear = -1;
If front == rear, there is only one element in the queue.
After deleting it, both front and rear are set to -1, indicating that the queue is empty.
else
front = (front + 1) % 5;
This moves front to the next position.
For example, if front = 2:
[ (2+1)%5=3 ]
Now, front = 3.
}
break;
case 3:
if (front == -1)
cout << "Queue is Empty";
else
{
i = front;
The variable i starts at the front position because we want to display elements from the beginning of the queue.
while (true)
{
cout << q[i] << " ";
if (i == rear)
When i reaches rear, the last element has been displayed. break stops the loop.
break;
i = (i + 1) % 5;
}
}
break;
}
} while (choice != 4);
return 0;
}
Thursday, 15 October 2026
Write a Program to implement the queue and Display no.of elements.
int front = 0;
int rear = -1;
int count = 0;
front → points to the first element.
rear → points to the last element.
count → stores the number of elements in the queue.
For example:
Queue: 10 20 30
↑ ↑
front rear
count = 3
When 10 is deleted:
Queue: 20 30
↑ ↑
front rear
count = 2
Enqueue = Insert
Dequeue = Delete
Count = Number of elements
#include <iostream>
using namespace std;
int queue[5];
int front = 0;
int rear = -1;
int count = 0;
// Insert element into Queue
void enqueue(int value)
{
if (count == 5)
{
cout << "Queue is Full" << endl;
}
else
{
rear++;
queue[rear] = value;
Count++;
cout << value << " inserted" << endl;
}
}
// Delete element from Queue
void dequeue()
{
if (count == 0)
{
cout << "Queue is Empty" << endl;
}
else
{
cout << queue[front] << " deleted" << endl;
front++;
count--;
}
}
// Peek/Front - View the first element
void peek()
{
if (count == 0)
{
cout << "Queue is Empty" << endl;
}
else
{
cout << "Front element: " << queue[front] << endl;
}
}
// Display Queue
void display()
{
if (count == 0)
{
cout << "Queue is Empty" << endl;
}
else
{
cout << "Queue elements: ";
for (int i = front; i <= rear; i++)
{
cout << queue[i] << " ";
}
cout << endl;
}
}
// Display number of elements
void displayCount()
{
cout << "Number of elements: " << count << endl;
}
int main()
{
enqueue(10);
enqueue(20);
enqueue(30);
display();
displayCount();
dequeue();
peek();
display();
displayCount();
return 0;
}
Write a Program to implement a Dynamic queue.(Pointer ,Linked List)
//rear- Last
//front-first
#include <iostream>
using namespace std;
// Structure for a Node
struct Node {
int data; // Stores the value
Node* next; // Stores the address of the next node
};
// Front and Rear pointers
Node* front = NULL;
Node* rear = NULL;
// Enqueue operation
void enqueue(int value) {
// Create a new node
Node* newNode = new Node;
// Store the value
newNode->data = value;
newNode->next = NULL;
// If queue is empty
if (rear == NULL) {
front = rear = newNode;
}
else {
// Add new node at the rear
rear->next = newNode;
rear = newNode;
}
cout << value << " inserted into queue" << endl;
}
// Dequeue operation
void dequeue() {
// Check if queue is empty
if (front == NULL) {
cout << "Queue is empty" << endl;
return;
}
// Store the front node temporarily
Node* temp = front;
// Display the value being removed
cout << temp->data << " deleted from queue" << endl;
// Move front to the next node
front = front->next;
// If queue becomes empty
if (front == NULL) {
rear = NULL;
}
// Delete the old front node
delete temp;
}
// Display queue
void display() {
// Check if queue is empty
if (front == NULL) {
cout << "Queue is empty" << endl;
return;
}
Node* temp = front;
cout << "Queue: ";
while (temp != NULL) {
cout << temp->data << " ";
temp = temp->next;
}
cout << endl;
}
// Main function
int main() {
// Insert elements
enqueue(10);
enqueue(20);
enqueue(30);
// Display queue
display();
// Delete one element
dequeue();
// Display queue again
display();
return 0;
}
Tuesday, 6 October 2026
C++ program to implement a Dynamic Stack using Pointer and Linked List.
#include <iostream>
using namespace std;
// Structure for a Node
struct Node {
int data; // Stores the value
Node* next; // Stores the address of the next node
};
// Top pointer of the stack
Node* top = NULL;
// Push operation
void push(int value) {
// Create a new node
Node* newNode = new Node;
// Store the value
newNode->data = value;
// Connect new node to the current top
newNode->next = top;
// Make new node the new top
top = newNode;
cout << value << " pushed
into stack" << endl;
}
// Pop operation
void pop() {
// Check if stack is empty
if (top == NULL) {
cout << "Stack is
empty" << endl;
return;
}
// Store the top node temporarily
Node* temp = top;
// Display the value being removed
cout << temp->data << "
popped from stack" << endl;
// Move top to the next node
top = top->next;
// Delete the old top node
delete temp;
}
// Display stack
void display() {
// Check if stack is empty
if (top == NULL) {
cout << "Stack is
empty" << endl;
return;
}
// Start from the top
Node* temp = top;
cout << "Stack: ";
// Display all nodes
while (temp != NULL) {
cout << temp->data <<
" ";
temp = temp->next;
}
cout << endl;
}
int main() {
// Push elements
push(10);
push(20);
push(30);
display();
pop();
display();
return 0;
}
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