This is a Java Program to implement a queue using array. Queue is a particular kind of abstract data type or collection in which the entities in the collection are kept in order and the principal (or only) operations on the collection are the addition of entities to the rear terminal position and removal of entities from the front terminal position. This makes queue a First-In-First-Out (FIFO) data structure.
Here is the source code of the Java Program to implement a queue using array. The Java program is successfully compiled and run on a Windows system. The program output is also shown below.
/* * Java Program to Implement Queue */ import java.util.*; /* Class arrayQueue */ class arrayQueue { protected int Queue[] ; protected int front, rear, size, len; /* Constructor */ public arrayQueue(int n) { size = n; len = 0; Queue = new int[size]; front = -1; rear = -1; } /* Function to check if queue is empty */ public boolean isEmpty() { return front == -1; } /* Function to check if queue is full */ public boolean isFull() { return front==0 && rear == size -1 ; } /* Function to get the size of the queue */ public int getSize() { return len ; } /* Function to check the front element of the queue */ public int peek() { if (isEmpty()) throw new NoSuchElementException("Underflow Exception"); return Queue[front]; } /* Function to insert an element to the queue */ public void insert(int i) { if (rear == -1) { front = 0; rear = 0; Queue[rear] = i; } else if (rear + 1 >= size) throw new IndexOutOfBoundsException("Overflow Exception"); else if ( rear + 1 < size) Queue[++rear] = i; len++ ; } /* Function to remove front element from the queue */ public int remove() { if (isEmpty()) throw new NoSuchElementException("Underflow Exception"); else { len-- ; int ele = Queue[front]; if ( front == rear) { front = -1; rear = -1; } else front++; return ele; } } /* Function to display the status of the queue */ public void display() { System.out.print("\nQueue = "); if (len == 0) { System.out.print("Empty\n"); return ; } for (int i = front; i <= rear; i++) System.out.print(Queue[i]+" "); System.out.println(); } } /* Class QueueImplement */ public class QueueImplement { public static void main(String[] args) { Scanner scan = new Scanner(System.in); System.out.println("Array Queue Test\n"); System.out.println("Enter Size of Integer Queue "); int n = scan.nextInt(); /* creating object of class arrayQueue */ arrayQueue q = new arrayQueue(n); /* Perform Queue Operations */ char ch; do{ System.out.println("\nQueue Operations"); System.out.println("1. insert"); System.out.println("2. remove"); System.out.println("3. peek"); System.out.println("4. check empty"); System.out.println("5. check full"); System.out.println("6. size"); int choice = scan.nextInt(); switch (choice) { case 1 : System.out.println("Enter integer element to insert"); try { q.insert( scan.nextInt() ); } catch(Exception e) { System.out.println("Error : " +e.getMessage()); } break; case 2 : try { System.out.println("Removed Element = "+q.remove()); } catch(Exception e) { System.out.println("Error : " +e.getMessage()); } break; case 3 : try { System.out.println("Peek Element = "+q.peek()); } catch(Exception e) { System.out.println("Error : "+e.getMessage()); } break; case 4 : System.out.println("Empty status = "+q.isEmpty()); break; case 5 : System.out.println("Full status = "+q.isFull()); break; case 6 : System.out.println("Size = "+ q.getSize()); break; default : System.out.println("Wrong Entry \n "); break; } /* display Queue */ q.display(); System.out.println("\nDo you want to continue (Type y or n) \n"); ch = scan.next().charAt(0); } while (ch == 'Y'|| ch == 'y'); } }
Array Queue Test Enter Size of Integer Queue 5 Queue Operations 1. insert 2. remove 3. peek 4. check empty 5. check full 6. size 4 Empty status = true Queue = Empty Do you want to continue (Type y or n) y Queue Operations 1. insert 2. remove 3. peek 4. check empty 5. check full 6. size 1 Enter integer element to insert 24 Queue = 24 Do you want to continue (Type y or n) y Queue Operations 1. insert 2. remove 3. peek 4. check empty 5. check full 6. size 1 Enter integer element to insert 6 Queue = 24 6 Do you want to continue (Type y or n) y Queue Operations 1. insert 2. remove 3. peek 4. check empty 5. check full 6. size 1 Enter integer element to insert 16 Queue = 24 6 16 Do you want to continue (Type y or n) y Queue Operations 1. insert 2. remove 3. peek 4. check empty 5. check full 6. size 1 Enter integer element to insert 19 Queue = 24 6 16 19 Do you want to continue (Type y or n) y Queue Operations 1. insert 2. remove 3. peek 4. check empty 5. check full 6. size 1 Enter integer element to insert 32 Queue = 24 6 16 19 32 Do you want to continue (Type y or n) y Queue Operations 1. insert 2. remove 3. peek 4. check empty 5. check full 6. size 1 Enter integer element to insert 14 Error : Overflow Exception Queue = 24 6 16 19 32 Do you want to continue (Type y or n) y Queue Operations 1. insert 2. remove 3. peek 4. check empty 5. check full 6. size 5 Full status = true Queue = 24 6 16 19 32 Do you want to continue (Type y or n) y Queue Operations 1. insert 2. remove 3. peek 4. check empty 5. check full 6. size 3 Peek Element = 24 Queue = 24 6 16 19 32 Do you want to continue (Type y or n) y Queue Operations 1. insert 2. remove 3. peek 4. check empty 5. check full 6. size 2 Removed Element = 24 Queue = 6 16 19 32 Do you want to continue (Type y or n) y Queue Operations 1. insert 2. remove 3. peek 4. check empty 5. check full 6. size 2 Removed Element = 6 Queue = 16 19 32 Do you want to continue (Type y or n) y Queue Operations 1. insert 2. remove 3. peek 4. check empty 5. check full 6. size 6 Size = 3 Queue = 16 19 32 Do you want to continue (Type y or n) y Queue Operations 1. insert 2. remove 3. peek 4. check empty 5. check full 6. size 3 Peek Element = 16 Queue = 16 19 32 Do you want to continue (Type y or n) y Queue Operations 1. insert 2. remove 3. peek 4. check empty 5. check full 6. size 2 Removed Element = 16 Queue = 19 32 Do you want to continue (Type y or n) y Queue Operations 1. insert 2. remove 3. peek 4. check empty 5. check full 6. size 2 Removed Element = 19 Queue = 32 Do you want to continue (Type y or n) y Queue Operations 1. insert 2. remove 3. peek 4. check empty 5. check full 6. size 2 Removed Element = 32 Queue = Empty Do you want to continue (Type y or n) y Queue Operations 1. insert 2. remove 3. peek 4. check empty 5. check full 6. size 2 Error : Underflow Exception Queue = Empty Do you want to continue (Type y or n) y Queue Operations 1. insert 2. remove 3. peek 4. check empty 5. check full 6. size 4 Empty status = true Queue = Empty Do you want to continue (Type y or n) n
Related posts:
Java String Conversions
Pagination and Sorting using Spring Data JPA
Java Program to Implement RoleList API
Overflow and Underflow in Java
Beans and Dependency Injection
Spring Cloud AWS – Messaging Support
Java Program to Implement Red Black Tree
Java Program to Implement Self Balancing Binary Search Tree
Java Program to Implement Quick sort
Guide to the Java ArrayList
Servlet 3 Async Support with Spring MVC and Spring Security
JUnit5 @RunWith
Java Program to Describe the Representation of Graph using Incidence List
Convert char to String in Java
HttpClient Connection Management
Guide To CompletableFuture
Java Program to Create a Random Linear Extension for a DAG
How to Replace Many if Statements in Java
Hướng dẫn sử dụng Java Reflection
Java Program to Implement Max Heap
Java Program to Implement LinkedHashMap API
Java Program to Implement Suffix Array
Handle EML file with JavaMail
Spring Boot - Servlet Filter
Send email with SMTPS (eg. Google GMail)
Java Program to Apply DFS to Perform the Topological Sorting of a Directed Acyclic Graph
Simple Single Sign-On with Spring Security OAuth2
The Difference Between map() and flatMap()
RegEx for matching Date Pattern in Java
Java Program to Implement Dijkstra’s Algorithm using Queue
Arrays.asList vs new ArrayList(Arrays.asList())
Spring Security – Reset Your Password