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Author: cricksmaidiene

QueueArray.java

@@ -0,0 +1,159 @@
+import java.io.*;
+import java.util.*;
+class QueueArray{
+
+	Scanner sc = new Scanner(System.in);
+	int queue[];
+	int front=0,rear=0,size=0,n=0;
+
+	public static void main(String args[])throws IOException{
+		
+		QueueArray Queue = new QueueArray();
+		Queue.Driver();
+	}
+	
+	public void Driver(){	
+		
+		String in=""; 
+		int elem=0;
+
+		System.out.print("Enter the size of the Queue: ");
+		if(ZeroQueue()) return;
+
+		CreateQueue(n);
+		boolean INTR=true;
+		do{
+			int choice = QueueMenu();
+			switch (choice){
+				case (1):
+				{
+					if(!QueueIsFull()){	
+						System.out.print("ENQUEUE: ");
+						in = SafeInput();
+						if(in.equals("invalid")){
+							sc.nextLine();
+							break;
+						}
+						elem = Integer.parseInt(in);
+						Enqueue(elem);
+						System.out.println(elem+" has been added to the queue");
+					}
+					else
+						System.out.println("Queue is full");
+					break;		
+				}
+				case (2):
+				{
+					if(!QueueIsEmpty()){
+						elem = Dequeue();
+						System.out.println("Dequeued element: "+elem);
+					}
+					else
+						System.out.println("Queue is empty");	
+					break;
+				}
+				case (3):
+				{
+					if(!QueueIsEmpty())
+						System.out.println("Front element is: "+queue[front]);
+					else
+						System.out.println("Queue is empty");	
+					break;
+				}
+				case (4):
+				{
+					System.out.println("Size of Queue is "+ size);
+					break;
+				}
+				case (5):
+				{
+					if(!QueueIsEmpty()){
+						System.out.print("QUEUE: ( ");
+						Display();
+						System.out.println(")");
+					}
+					else
+						System.out.println("Queue is empty");	
+					break;
+				}
+				case (0):
+					INTR=false;
+
+			}
+			if(choice>5||choice<0)
+				System.out.println("Not a valid menu option");
+
+		}while(INTR);	
+	}
+	
+	public boolean ZeroQueue(){
+		String in="";
+		in = SafeInput();
+		if(in.equals("invalid"))
+			return true;
+		
+		n = Integer.parseInt(in);
+		if(n<=0){
+			System.out.println("No worthwhile queue size. Exiting...");
+		 	return true;
+		}
+		return false; 	
+	}
+	
+	public String SafeInput(){
+		int a;
+		try{
+				a=sc.nextInt();
+				return Integer.toString(a);
+			}	
+			catch(InputMismatchException e)
+			{
+				System.out.println("Result not an integer");
+				return "invalid";
+			}
+	}
+
+	public void CreateQueue(int n){
+		queue = new int[n];
+	}
+
+	public int QueueMenu(){
+		System.out.println("QUEUE OPTIONS: ");
+		System.out.println("1.ENQUEUE 2.DEQUEUE 3.FRONT 4.SIZE 5.DISPLAY 0.EXIT");
+		String in = SafeInput();
+		if(in=="invalid"){
+			sc.nextLine();
+			return -1;
+		}
+		else return Integer.parseInt(in);
+	}
+
+	public void Enqueue(int elem){
+		queue[rear]=elem;
+		rear = (++rear)%n;
+		++size;
+	}
+	public int Dequeue(){
+		int elem = queue[front];
+		front = (++front)%n;
+		--size;
+		return elem;
+	}
+	public void Display(){
+		for(int i=front,j=0;j<size;j++){
+			System.out.print(queue[i] +" ");
+			i=(i+1)%n;
+		}
+	}
+	public boolean QueueIsFull(){
+		boolean value;
+		value = ((size==n) ? true : false);
+		return value;
+	}
+	public boolean QueueIsEmpty(){
+		boolean value;
+		value = (size==0) ? true : false;
+		return value;
+	}
+
+}