Lab 8 - Queue from Array

#include <iostream>
using namespace std;
int queue[100], n = 100, front = - 1, rear = - 1;
void Insert()
{
    int val;
    if (rear == n - 1)
        cout<<"Queue Overflow"<<endl;
    else
    {
        if (front == - 1)
            front = 0;
        cout<<"Insert the element in queue : "<<endl;
        cin>>val;
        rear++;
        queue[rear] = val;
    }
}
void Delete()
{
    if (front == - 1 || front > rear)
    {
        cout<<"Queue Underflow ";
        return ;
    }
    else
    {
        cout<<"Element deleted from queue is : "<< queue[front] <<endl;
        front++;;
    }
}
void Display()
{
    if (front == - 1)
        cout<<"Queue is empty"<<endl;
    else
    {
        cout<<"Queue elements are : ";
        for (int i = front; i <= rear; i++)
            cout<<queue[i]<<" ";
        cout<<endl;
    }
}
int main()
{
    int ch;
    cout<<"1) Insert element to queue"<<endl;
    cout<<"2) Delete element from queue"<<endl;
    cout<<"3) Display all the elements of queue"<<endl;
    cout<<"4) Exit"<<endl;
    do
    {
        cout<<"Enter your choice : "<<endl;
        cin>>ch;
        switch (ch)
        {
        case 1:
            Insert();
            break;
        case 2:
            Delete();
            break;
        case 3:
            Display();
            break;
        case 4:
            cout<<"Exit"<<endl;
            break;
        default:
            cout<<"Invalid choice"<<endl;
        }
    }
    while(ch!=4);
    return 0;
}