12b- Queues template

/**************************************

13b) Write a C++ program to create a class called QUEUE with member functions to add an
element and to delete an element from the queue. Using these member functions, implement a
queue of integers and doubles. Demonstrate the operations by displaying the contents of the queue
after every operation.

****************************************/

#include <iostream>
#define QSIZE 6
using namespace std;
int i;

template <class X>
class que
{
	int r=-1;
	int f=0;
	X q[QSIZE];

public:
	void add(X);
	void Delete();
	void display();
};


template <class X>
void que<X>::add(X item)
{
	if(r==QSIZE-1)
		cout<<"Cannot Insert. que is full"<<endl;
	else
	{
		q[++r] = item;
	}
}


template <class X>
void que<X>::Delete()
{
	if(f>r)
		cout<<"que is Empty."<<endl;
	else
	{
		cout<<"Item deleted is "<<q[f]<<endl;
		f++;

		if(f>r)
		{
			f=0;
			r=-1;
		}
	}
}


template <class X>
void que<X>::display()
{
	if(f>r)
	{
		cout<<"The que is empty"<<endl;
	}

	cout<<"The contents of the que are: "<<endl;

	for(i=f; i<=r; i++)
	{
		cout<<q[i]<<endl;
	}
}

void integerchoice(que<int> qi)
{
	int item;
	int choice;

	while(1)
	{
		cout<<"1. Add integer"<<endl;
		cout<<"2. Delete integer"<<endl;
		cout<<"3. Display"<<endl;

		cin>>choice;
		switch(choice)
		{
			case 1:
				cout<<"Item? ";
				cin>>item;
				qi.add(item);
				break;

			case 2:
				qi.Delete();
				break;

			case 3:
				qi.display();
		}
	}
}
void doublechoice(que<double> qd)
{
	double item;
	int choice;

	while(1)
	{
		cout<<"1. Add double"<<endl;
		cout<<"2. Delete double"<<endl;
		cout<<"3. Display"<<endl;

		cin>>choice;
		switch(choice)
		{
			case 1:
				cout<<"Item? ";
				cin>>item;
				qd.add(item);
				break;

			case 2:
				qd.Delete();
				break;

			case 3:
				qd.display();
		}
	}
}

int main()
{
	que<int> qi;
	que<double> qd;

	int choice;
	while(1)
	{
		cout<<"Enter a choice: "<<endl;
		cout<<"1. que of Integers."<<endl;
		cout<<"2. que of doubles."<<endl;
		cin>>choice;

		switch(choice)
		{
			case 1:
				integerchoice(qi);
				break;
			case 2:
				doublechoice(qd);
				break;
		}

	}

}