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implementation of queue using linked list in c

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Digvijay Sunil answered on March 28, 2022 Popularity 9/10 Helpfulness 3/10

answer implementation of queue using linked list in c

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implementation of queue using linked list in c

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#include <stdio.h>
#include <stdlib.h>

// Structure to create a node with data and next pointer
struct node {
	int data;
	struct node *next;
};

struct node *front = NULL;
struct node *rear = NULL;

// Enqueue() operation on a queue
void enqueue(int value) {
	struct node *ptr;
	ptr = (struct node *)malloc(sizeof(struct node));
	ptr->data = value;
	ptr->next = NULL;
	if ((front == NULL) && (rear == NULL)) {
		front = rear = ptr;
	} else {
		rear->next = ptr;
		rear = ptr;
	}
	printf("Node is Inserted\n\n");
}

// Dequeue() operation on a queue
int dequeue() {
	if (front == NULL) {
		printf("\nUnderflow\n");
		return -1;
	} else {
		struct node *temp = front;
		int temp_data = front->data;
		front = front->next;
		free(temp);
		return temp_data;
	}
}

// Display all elements of queue
void display() {
	struct node *temp;
	if ((front == NULL) && (rear == NULL)) {
		printf("\nQueue is Empty\n");
	} else {
		printf("The queue is \n");
		temp = front;
		while (temp) {
			printf("%d--->", temp->data);
			temp = temp->next;
		}
		printf("NULL\n\n");
	}
}

int main() {
	int choice, value;
	printf("\nImplementation of Queue using Linked List\n");
	while (choice != 4) {
		printf("1.Enqueue\n2.Dequeue\n3.Display\n4.Exit\n");
		printf("\nEnter your choice : ");
		scanf("%d", &choice);
		switch (choice) {
		case 1:
			printf("\nEnter the value to insert: ");
			scanf("%d", &value);
			enqueue(value);
			break;
		case 2:
			printf("Popped element is :%d\n", dequeue());
			break;
		case 3:
			display();
			break;
		case 4:
			exit(0);
			break;
		default:
			printf("\nWrong Choice\n");
		}
	}
	return 0;
}

Popularity 9/10 Helpfulness 3/10 Language c

Source: www.scaler.com

Tags: c implementation linked-list queue using

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Contributed on Sep 20 2022

Digvijay Sunil

0 Answers Avg Quality 2/10

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queue implementation using linked list in cpp

Comment

#include<iostream>
using namespace std;

struct node
{
	int value;
	node* next;
};

class Queue
{
private:
	node* front;
	node* rear;
public:
	Queue()
	{
		front = rear = NULL;
	}
	void EnQueue(int n)
	{
		node* temp = new node();
		temp->value = n;
		temp->next = NULL;

		if (front == NULL && rear == NULL)
		{
			front = rear = temp;
			return;
		}
		rear->next = temp;
		rear = temp;
	}
	void Dequeue()
	{
		node* temp = front;

		if (front == NULL)
		{
			cout << "Queue is empty!\n";
			return;
		}
		else if (front == rear)
		{
			front = rear = NULL;
		}
		else
		{
			front = front->next;
		}

		delete temp;
	}
	int getFront()
	{
		if (front == NULL)
		{
			cout << "Queue is empty!\n";
		}
		else
		{
			return front->value;
		}
	}
	void Display()
	{
		node* temp = front;
		cout << "Queue Item: ";
		while (temp != NULL)
		{
			cout << temp->value << " ";
			temp = temp->next;
		}
		cout << "\n";
	}
};
int main()
{
	Queue q;

	q.EnQueue(1);
	q.EnQueue(2);
	q.EnQueue(3);
	q.EnQueue(4);
	q.EnQueue(5);

	q.Display();  //should print [1 2 3 4 5]

	cout << q.getFront() << "\n";  //should print [1]

	q.Dequeue();   //should delete [1]
	q.Dequeue();  //should delete [2]

	q.Display();  //should print [3 4 5]

	cout << q.getFront() << "\n";  //should print [3]

	return 0;
}

Popularity 9/10 Helpfulness 6/10 Language cpp

Source: www.codegrepper.com

Tags: c++

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Contributed on Mar 28 2022

coder

0 Answers Avg Quality 2/10

implementation of queue using linked list in c

Comment

#include <stdio.h>
#include <stdlib.h>

// Structure to create a node with data and next pointer
struct node {
	int data;
	struct node *next;
};

struct node *front = NULL;
struct node *rear = NULL;

// Enqueue() operation on a queue
void enqueue(int value) {
	struct node *ptr;
	ptr = (struct node *)malloc(sizeof(struct node));
	ptr->data = value;
	ptr->next = NULL;
	if ((front == NULL) && (rear == NULL)) {
		front = rear = ptr;
	} else {
		rear->next = ptr;
		rear = ptr;
	}
	printf("Node is Inserted\n\n");
}

// Dequeue() operation on a queue
int dequeue() {
	if (front == NULL) {
		printf("\nUnderflow\n");
		return -1;
	} else {
		struct node *temp = front;
		int temp_data = front->data;
		front = front->next;
		free(temp);
		return temp_data;
	}
}

// Display all elements of queue
void display() {
	struct node *temp;
	if ((front == NULL) && (rear == NULL)) {
		printf("\nQueue is Empty\n");
	} else {
		printf("The queue is \n");
		temp = front;
		while (temp) {
			printf("%d--->", temp->data);
			temp = temp->next;
		}
		printf("NULL\n\n");
	}
}

int main() {
	int choice, value;
	printf("\nImplementation of Queue using Linked List\n");
	while (choice != 4) {
		printf("1.Enqueue\n2.Dequeue\n3.Display\n4.Exit\n");
		printf("\nEnter your choice : ");
		scanf("%d", &choice);
		switch (choice) {
		case 1:
			printf("\nEnter the value to insert: ");
			scanf("%d", &value);
			enqueue(value);
			break;
		case 2:
			printf("Popped element is :%d\n", dequeue());
			break;
		case 3:
			display();
			break;
		case 4:
			exit(0);
			break;
		default:
			printf("\nWrong Choice\n");
		}
	}
	return 0;
}

Popularity 10/10 Helpfulness 4/10 Language c

Source: www.scaler.com

Tags: c

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Contributed on Sep 20 2022

Digvijay Sunil

0 Answers Avg Quality 2/10

queue implementation using linked list in cpp

Comment

#include<iostream>
using namespace std;

struct node
{
	int value;
	node* next;
};

class Queue
{
private:
	node* front;
	node* rear;
public:
	Queue()
	{
		front = rear = NULL;
	}
	void EnQueue(int n)
	{
		node* temp = new node();
		temp->value = n;
		temp->next = NULL;

		if (front == NULL && rear == NULL)
		{
			front = rear = temp;
			return;
		}
		rear->next = temp;
		rear = temp;
	}
	void Dequeue()
	{
		node* temp = front;

		if (front == NULL)
		{
			cout << "Queue is empty!\n";
			return;
		}
		else if (front == rear)
		{
			front = rear = NULL;
		}
		else
		{
			front = front->next;
		}

		delete temp;
	}
	int getFront()
	{
		if (front == NULL)
		{
			cout << "Queue is empty!\n";
		}
		else
		{
			return front->value;
		}
	}
	void Display()
	{
		node* temp = front;
		cout << "Queue Item: ";
		while (temp != NULL)
		{
			cout << temp->value << " ";
			temp = temp->next;
		}
		cout << "\n";
	}
};
int main()
{
	Queue q;

	q.EnQueue(1);
	q.EnQueue(2);
	q.EnQueue(3);
	q.EnQueue(4);
	q.EnQueue(5);

	q.Display();  //should print [1 2 3 4 5]

	cout << q.getFront() << "\n";  //should print [1]

	q.Dequeue();   //should delete [1]
	q.Dequeue();  //should delete [2]

	q.Display();  //should print [3 4 5]

	cout << q.getFront() << "\n";  //should print [3]

	return 0;
}

Popularity 9/10 Helpfulness 2/10 Language cpp

Source: www.codegrepper.com

Tags: c++ implementation i

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Contributed on Mar 28 2022

coder

0 Answers Avg Quality 2/10

Queue using linked list

Comment

#include<iostream>
using namespace std;

class node{
	public:
		int data;
		node *next;
		void EnQueue();
		void DeQueue();
		void display();
};
node *rear=NULL;
void node::EnQueue()
{
	
		
	if(rear==NULL)
	{
		rear=new node();
			cout<<"Enter data : ";
			cin>>rear->data;
	}
	else
	{
	static node *temp=rear;
	node *newnode;
	newnode=new node();
	cout<<"Enter data : ";
	cin>>newnode->data;
	newnode->next=NULL;
	temp->next=newnode;
	temp=temp->next;
	}
}

void node::DeQueue()
{
	if(rear==NULL)
	{
		cout<<"The Queue is Underflow!";
	}
	else
	{
	cout<<"Dequeued element is : "<<rear->data;
	rear=rear->next;
	}
}

void node::display()
{
	node* temp=rear;
	if(rear==NULL)
	{
		cout<<"\nThe Queue is Empty!\n";
	}
	else
	{
		while(temp!=NULL)
		{
		cout<<temp->data<<" ";
		temp=temp->next;
		}
	}
}
int main()
{
	node obj;
 int ch;
   
    while(ch!=4){
    	cout<<"\n1) Push in stack"<<endl;
   		cout<<"2) Pop from stack"<<endl;
   		cout<<"3) Display stack"<<endl;
  		cout<<"4) Exit"<<endl;
    	cout<<"Enter choice: "<<endl;
      cin>>ch;
      switch(ch) {
         case 1: {
            obj.EnQueue();
            break;
         }
         case 2: {
            obj.DeQueue();
            break;
         }
         case 3: {
            obj.display();
            break;
         }
         case 4: {
            exit(0);
            break;
         }
         default: {
            cout<<"Invalid Choice"<<endl;
         }
	
}
}
}

Popularity 8/10 Helpfulness 2/10 Language cpp

Source: Grepper

Tags: c++ linked-list

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Contributed on Sep 06 2023

talha shahid

0 Answers Avg Quality 2/10

Linked List Implementation of a Queue

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// A C program to demonstrate linked list based implementation of queue
#include <stdio.h>
#include <stdlib.h>
  
// A linked list (LL) node to store a queue entry
struct QNode {
    int key;
    struct QNode* next;
};
  
// The queue, front stores the front node of LL and rear stores the
// last node of LL
struct Queue {
    struct QNode *front, *rear;
};
  
// A utility function to create a new linked list node.
struct QNode* newNode(int k)
{
    struct QNode* temp = (struct QNode*)malloc(sizeof(struct QNode));
    temp->key = k;
    temp->next = NULL;
    return temp;
}
  
// A utility function to create an empty queue
struct Queue* createQueue()
{
    struct Queue* q = (struct Queue*)malloc(sizeof(struct Queue));
    q->front = q->rear = NULL;
    return q;
}
  
// The function to add a key k to q
void enQueue(struct Queue* q, int k)
{
    // Create a new LL node
    struct QNode* temp = newNode(k);
  
    // If queue is empty, then new node is front and rear both
    if (q->rear == NULL) {
        q->front = q->rear = temp;
        return;
    }
  
    // Add the new node at the end of queue and change rear
    q->rear->next = temp;
    q->rear = temp;
}
  
// Function to remove a key from given queue q
void deQueue(struct Queue* q)
{
    // If queue is empty, return NULL.
    if (q->front == NULL)
        return;
  
    // Store previous front and move front one node ahead
    struct QNode* temp = q->front;
  
    q->front = q->front->next;
  
    // If front becomes NULL, then change rear also as NULL
    if (q->front == NULL)
        q->rear = NULL;
  
    free(temp);
}
  
// Driver Program to test above functions
int main()
{
    struct Queue* q = createQueue();
    enQueue(q, 10);
    enQueue(q, 20);
    deQueue(q);
    deQueue(q);
    enQueue(q, 30);
    enQueue(q, 40);
    enQueue(q, 50);
    deQueue(q);
    printf("Queue Front : %d \n", q->front->key);
    printf("Queue Rear : %d", q->rear->key);
    return 0;
}

Popularity 10/10 Helpfulness 1/10 Language whatever

Source: www.geeksforgeeks.org

Tags: implementation impl

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Contributed on Aug 28 2022

Said HR

0 Answers Avg Quality 2/10

implementation of queue using linked list in c

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