Program for Priority Queue in CPP

Queue.cpp

#include<iostream>
using namespace std;

int rear=-1;
int front=-1;
int q[10];

bool isfull()
{
    if(rear==9)
    {
        return 1;
    }
    else
        return 0;
}
bool isempty()
{
    if(front==-1)
    {
        return 1;
    }
    else
        return 0;
}
int display()
{
    if(isempty())
    {
        cout<<"Queue is empty!"<<endl;
    }
    else
    {
        for(int i=front;i<=rear;i++)
        {
            cout<<q[i]<<"->";
        }
    }
}
int main()
{
    int ch,data,count;
    while(ch!=-1)
    {
        cout<<"n----MENU----"<<endl;
        cout<<"1.Insert"<<endl;
        cout<<"2.Delete"<<endl;
        cout<<"3.Display"<<endl;
        cout<<"4.Exit"<<endl;
        cout<<"Enter a choice:";
        cin>>ch;
        switch(ch)
        {
            case 1:
                int i;
                if(isfull())
                {
                    cout<<"Queue is full!"<<endl;
                    display();
                    break;
                }
                else
                {
                    if(isempty())
                    {
                        front=0;
                        cout<<"Enter a data:";
                        cin>>data;
                        q[front]=data;
                        rear=0;
                    }
                    else
                    {
                        cout<<"Enter a data:";
                        cin>>data;
                        for(i=rear;i>=front;i--)
                        {
                            if(data>q[i])
                            {
                                q[i+1]=q[i];
                            }
                            else
                            {
                                break;
                            }
                        }   
                        q[i+1]=data;
                    rear=rear+1;
                    }
                display();  
                break;
                }
            case 2:
                if(isempty())
                {
                    cout<<"Queue underflow!"<<endl;
                    break;  
                }
                else
                {
                    data=q[front];
                    cout<<q[front]<<" is deleted!"<<endl;
                    front=front+1;
                    if(front>rear)
                    {
                        front=rear=-1;
                    }
                    display();
                    break;
                }
            case 3:
                display();
                break;  
            case 4:
                exit(0);
        }
    }
}