queue.cpp

#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 && ch>0);

   return 0;
}