Merge pull request larissalages#126 from Divyanshu-info/master

Added Circular queue

Author: larissalages

.gitignore

@@ -0,0 +1,2 @@
+
+*.exe

data_structures/C++/circularqueue.cpp

@@ -0,0 +1,166 @@
+#include <iostream>
+#include <stack>
+using namespace std;
+
+#define SIZE 10
+
+class CircularQueue
+{
+    int a[SIZE];
+    int rear;
+    int front;
+
+public:
+    CircularQueue()
+    {
+        rear = front = -1;
+    }
+
+    bool isFull()
+    {
+        if (front == 0 && rear == SIZE - 1)
+        {
+            return true;
+        }
+        if (front == rear + 1)
+        {
+            return true;
+        }
+        return false;
+    }
+
+    bool isEmpty()
+    {
+        if (front == -1)
+        {
+            return true;
+        }
+        else
+        {
+            return false;
+        }
+    }
+
+    void enqueue(int x);
+    int dequeue();
+    void display();
+    int size();
+};
+
+void CircularQueue ::enqueue(int x)
+{
+    if (isFull())
+    {
+        cout << "Queue is full";
+    }
+    else
+    {
+        if (front == -1)
+        {
+            front = 0;
+        }
+        rear = (rear + 1) % SIZE;
+
+        a[rear] = x;
+        cout << endl
+             << "Inserted " << x << endl;
+    }
+}
+
+int CircularQueue ::dequeue()
+{
+    int y;
+
+    if (isEmpty())
+    {
+        cout << "Queue is empty\n"
+             << endl;
+    }
+    else
+    {
+        y = a[front];
+        if (front == rear)
+        {
+            front = -1;
+            rear = -1;
+        }
+        else
+        {
+            front = (front + 1) % SIZE;
+        }
+        return (y);
+    }
+}
+
+void CircularQueue ::display()
+{
+    int i;
+    if (isEmpty())
+    {
+        cout << endl
+             << "\nEmpty Queue\n"
+             << endl;
+    }
+    else
+    {
+        cout << endl
+             << "Front -> " << front;
+        cout << endl
+             << "Elements -> ";
+        for (i = front; i != rear; i = (i + 1) % SIZE)
+        {
+            cout << a[i] << "\t";
+        }
+        cout << a[i];
+        cout << endl
+             << "Rear -> " << rear << "\n";
+    }
+}
+
+int CircularQueue ::size()
+{
+    if (rear >= front)
+    {
+        return (rear - front) + 1;
+    }
+    else
+    {
+        return (SIZE - (front - rear) + 1);
+    }
+}
+
+int main()
+{
+    CircularQueue cq;
+    int n;
+    int x;
+    while (1)
+    {
+        cout << "\n1. enqueue\n2. dequeue\n3. size\n4. Display Elements\n5. Exit\n";
+        cin >> n;
+        switch (n)
+        {
+        case 1:
+            cout << "Enter  the No. ";
+            cin >> x;
+            cq.enqueue(x);
+            break;
+
+        case 2:
+            cout << "Removed element: " << cq.dequeue() << endl;
+            break;
+        case 3:
+            cout << endl
+                 << "Size of queue: " << cq.size() << endl;
+            break;
+        case 4:
+            cq.display();
+            break;
+        case 5:
+            return 0;
+            break;
+        default:
+            break;
+        }
+    }
+}