DSL

11: Problem Statement:
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.
Program Code:
#include <iostream>
using namespace std;
#define size 5

class spq
{
    int f,r,job,djob;            //data members
    int simpq[size],prioq[size];
public:
    spq() //Default constructor
    {
     f=r=-1; //init front and rear to -1.
     job=djob=0;
     prioq[-1]=0;
    }
    //To check Q is full or not
    int isQfull()
    {
        if(r==size-1)
            return 1;
        else
            return 0;
    }
    //To check Q is empty or not
    int isQempty()
    {
        if((f==-1)||(f>r))
            return 1;
        else
            return 0;
    }
    void simpqadd(); //member functions.
    void showsimpleQ();
    void delsimpleQ();
    void prioqadd();
    void delprioQ();
    void showprioQ();
};

//To insert the job inside the simple queue.
void spq::simpqadd()
{
    cout<<"\nEnter the Job: ";
    cin>>job;
    if(isQfull())
        cout<<"\nSorry !! Queue is full....\n";
    else
    {
        if(f==-1)
        {
            f=r=0;
            simpq[r]=job;
        }
        else
        {
            r=r+1;
            simpq[r]=job;
        }
    }

}

//To delete job from the simple queue.
void spq::delsimpleQ()
{
    if(isQempty())
        cout<<"\nSorry Q is empty...\n";
    else
    {
        djob=simpq[f];
        f=f+1;
        cout<<"\nDeleted job is: "<<djob;
    }
}

//To show all the jobs from SimpleQueue.
void spq::showsimpleQ()
{
    cout<<"\nThe simple Queue job are as follows....\n";
    int temp;
    for(temp=f;temp<=r;temp++)
    {
        cout<<"\t"<<simpq[temp];
    }
}

//To delete job from the simple queue.
void spq::delprioQ()
{
    if(isQempty())
        cout<<"\nSorry Q is empty...\n";
    else
    {
        djob=prioq[f];
        f=f+1;
        cout<<"\nDeleted job is: "<<djob;
    }
}

//To show all the jobs from PrioQueue.
void spq::showprioQ()
{
    cout<<"\nThe priority Queue job are as follows....\n";
    int temp;
    for(temp=f;temp<=r;temp++)
    {
        cout<<"\t"<<prioq[temp];
    }
}

//To add the jobs as per the priority.
void spq::prioqadd()
{
    int t=0;
    cout<<"\nEnter the job: ";
    cin>>job;
    if(isQfull())
        cout<<"\nSorry!! Priority Queue is full...\n";
    else
    {
        if(f==-1)
        {
            f=r=0; //initially when q is empty insert first job.
            prioq[r]=job;
        }
        else if(job<prioq[r]) //Check the priority(Ascending) of incoming job if it is high
        {
         t=r;
         while(job<prioq[t])//do until priority is high
         {
            prioq[t+1]=prioq[t]; //then shift all the jobs towards right
            t=t-1; //decrement index to check another job.
         }
         t=t+1; //increment index
         prioq[t]=job; //store job at its appropriate location.
         r=r+1; //increment rear index by one
        }
        else
        {
            r=r+1; // as per the priority store in Q.
            prioq[r]=job;
        }
    }
}

int main()
{
    spq s1,s2; //object creation. s1 for simple Q and s2 for priority Q
    int ch;
    do
    {
     cout<< "\n\t!!!Operating System Job Queue!!!" << endl; // prints the msg.
     cout<<"\n1.SimpleQ Add_Job\n2.SimpleQ Del_Job\n3.Show SimpleQ\n4.PrioQ Add_Job\n5.PrioQ Del_Job\n6.Show PrioQ";
     cout<<"\nEnter Your Choice:";
     cin>>ch;
     switch(ch)
     {
      case 1:s1.simpqadd();break;//calling adding element in simple Q without priority.
      case 2:s1.delsimpleQ();break;
      case 3:s1.showsimpleQ();break;
      case 4:s2.prioqadd();break;//calling adding element in priority Q with priority.
      case 5:s2.delprioQ();break;
      case 6:s2.showprioQ();break;
     }
    }while(ch!=7);
    return 0;
}