Create implement dynamic queue

implement dynamic queue

@@ -0,0 +1,293 @@
+// C++ program for the above approach
+#include <bits/stdc++.h>
+using namespace std;
+
+// Class definition for queue
+template <class X>
+class Queue {
+
+private:
+	// Stores the frontIndex
+	int frontIndex;
+
+	// Stores the back Index
+	int backIndex;
+
+	// Stores the array
+	X* arr;
+
+	// Stores the sizeof queue
+	int sizeVar;
+
+	// Stores the size of array
+	int capacityVar = 4;
+
+public:
+	// Queue class constructor
+	Queue()
+	{
+		arr = new X[capacityVar];
+		frontIndex = backIndex = -1;
+		sizeVar = 0;
+	}
+
+	// Function Methods
+	bool empty();
+	bool full();
+	void push(X x);
+	void pop();
+	X front();
+	X back();
+	int capacity();
+	int size();
+};
+
+// Find the capacity of queue
+template <class X>
+int Queue<X>::capacity()
+{
+	return capacityVar;
+}
+
+// Find the number of elements
+// present in Queue
+template <class X>
+int Queue<X>::size()
+{
+	return sizeVar;
+}
+
+// Function to check if
+// Queue is empty or not
+template <class X>
+bool Queue<X>::empty()
+{
+	if (frontIndex == -1
+		&& backIndex == -1)
+		return true;
+	else
+		return false;
+}
+
+// Function to check if the queue
+// is full or not
+template <class X>
+bool Queue<X>::full()
+{
+	if (sizeVar == capacityVar)
+		return true;
+	else
+		return false;
+}
+
+// Function to find the front element
+// of the queue
+template <class X>
+X Queue<X>::front()
+{
+	// If queue is empty
+	if (empty()) {
+		cout << "Queue underflow"
+			<< endl;
+		abort();
+	}
+
+	return arr[frontIndex];
+}
+
+// Function to find the last element
+// of the Queue
+template <class X>
+X Queue<X>::back()
+{
+	if (empty()) {
+		cout << "Queue underflow"
+			<< endl;
+		abort();
+	}
+	return arr[backIndex];
+}
+
+// Function to insert the element
+// to the rear end of the queue
+template <class X>
+void Queue<X>::push(X x)
+{
+	if (full()) {
+
+		// If the queue is full, then
+		// double the capacity
+		capacityVar = capacityVar * 2;
+
+		// Initialize new array of
+		// double size
+		X* temp = new X[capacityVar];
+
+		// Copy the elements of the
+		// previous array in the order of the queue
+		for (int i = 0, j= frontIndex; i < sizeVar; i++){
+		temp[i] = arr[j];
+		j = (j+1) % sizeVar;
+		}
+		// update the front and rear indices in the new array
+		frontIndex = 0;
+		backIndex = sizeVar -1;
+
+		// Deallocate the memory
+		// of previous array
+		delete[] arr;
+		arr = temp;
+	}
+
+	// If size is zero
+	if (empty()) {
+
+		frontIndex = backIndex = 0;
+		arr[backIndex] = x;
+		sizeVar++;
+		return;
+	}
+
+	// Increment the backIndex
+	backIndex = (backIndex + 1) % capacityVar;
+	arr[backIndex] = x;
+	sizeVar++;
+
+	return;
+}
+
+// Function to pop an element from
+// front end of the queue
+template <class X>
+void Queue<X>::pop()
+{
+	// If queue is empty
+	if (empty()) {
+		cout << "Queue underflow"
+			<< endl;
+		abort();
+	}
+
+	// If there is only one character
+	if (frontIndex == backIndex) {
+
+		// Mark Queue as empty
+		// and decrement sizeVar
+		frontIndex = backIndex = -1;
+		sizeVar--;
+		return;
+	}
+
+	// Increment frontIndex cyclically
+	// using modulo arithmetic
+	frontIndex = (frontIndex + 1) % capacityVar;
+	sizeVar--;
+
+	return;
+}
+
+// Driver Code
+int main()
+{
+	// Queue initialization
+	Queue<int> q;
+
+	// Iterate the range [1, 100]
+	for (int i = 1; i < 5; i++)
+		q.push(i);
+
+	// Print the current capacity
+	cout << "Current capacity "
+		<< q.capacity() << endl;
+
+	// Print current size
+	cout << "Current size "
+		<< q.size() << endl;
+
+	// Print front elements of queue
+	cout << "Front element "
+		<< q.front() << endl;
+
+	// Print last element of the queue
+	cout << "Rear element "
+		<< q.back() << endl;
+
+	cout << endl;
+
+	cout << "Pop an element" << endl;
+
+	// Pop an element from the queue
+	q.pop();
+
+	cout << "Pop an element" << endl;
+
+	// Pop an element from the queue
+	q.pop();
+
+	cout << endl;
+
+	// Print the current capacity
+	cout << "Current capacity "
+		<< q.capacity() << endl;
+
+	// Print current size
+	cout << "Current size "
+		<< q.size() << endl;
+
+	// Print front elements of queue
+	cout << "Front element "
+		<< q.front() << endl;
+
+	// Print last element of the queue
+	cout << "Rear element "
+		<< q.back() << endl;
+
+		cout << endl;
+	cout << "Push element 5" << endl;
+	cout << "Push element 6" << endl;
+
+
+	q.push(5);
+	q.push(6);
+	cout << endl;
+
+	// Print the current capacity
+	cout << "Current capacity "
+		<< q.capacity() << endl;
+
+	// Print current size
+	cout << "Current size "
+		<< q.size() << endl;
+
+	// Print front elements of queue
+	cout << "Front element "
+		<< q.front() << endl;
+
+	// Print last element of the queue
+	cout << "Rear element "
+		<< q.back() << endl;
+
+	cout << endl;
+	cout << "Push element 7" << endl;
+	q.push(7);
+
+	cout << endl;
+
+	// Print the current capacity
+	cout << "Current capacity "
+		<< q.capacity() << endl;
+
+	// Print current size
+	cout << "Current size "
+		<< q.size() << endl;
+
+	// Print front elements of queue
+	cout << "Front element "
+		<< q.front() << endl;
+
+	// Print last element of the queue
+	cout << "Rear element "
+		<< q.back() << endl;
+
+	return 0;
+}