Practical_29(C++).cpp

/*
Queues are frequently used in computer programming, and a typical example is the creation of a job queue by an operating system. 
If the operating system does not use priorities, then the jobs are processed in the order they enter the system.
Write C++ program for simulating job queue. Write functions to add job and delete job from queue.
*/

#include <iostream>
#define MAX 10
using namespace std;

struct queue {
    int data[MAX];
    int front, rear;
};

class Queue {
    struct queue q;

public:
    Queue() {
        q.front = q.rear = -1;
    }

    int isempty();
    int isfull();
    void enqueue(int);
    int delqueue();
    void display();
};

int Queue::isempty() {
    return (q.front == q.rear) ? 1 : 0;
}

int Queue::isfull() {
    return (q.rear == MAX - 1) ? 1 : 0;
}

void Queue::enqueue(int x) {
    q.data[++q.rear] = x;
}

int Queue::delqueue() {
    return q.data[++q.front];
}

void Queue::display() {
    int i;
    cout << "\n";
    for (i = q.front + 1; i <= q.rear; i++)
        cout << q.data[i] << " ";
}

int main() {
    Queue obj;
    int ch, x;
    do {
        cout << "\n 1. Insert Job\n 2. Delete Job\n 3. Display\n 4. Exit\n Enter your choice: ";
        cin >> ch;
        switch (ch) {
            case 1:
                if (!obj.isfull()) {
                    cout << "\n Enter data: ";
                    cin >> x;
                    obj.enqueue(x);
                    cout << endl;
                } else {
                    cout << "Queue is overflow!\n\n";
                }
                break;
            case 2:
                if (!obj.isempty())
                    cout << "\n Deleted Element = " << obj.delqueue() << endl;
                else {
                    cout << "\n Queue is underflow!\n\n";
                }
                cout << "\n Remaining Jobs: \n";
                obj.display();
                break;
            case 3:
                if (!obj.isempty()) {
                    cout << "\n Queue contains: \n";
                    obj.display();
                } else {
                    cout << "\n Queue is empty!\n\n";
                }
                break;
            case 4:
                cout << "\n Exiting Program...\n";
                break;
            default:
                cout << "\n Invalid Choice!\n";
        }
    } while (ch != 4);
    return 0;
}