Create queue_using_array.cpp (#707)

* Create queue_using_array.cpp

* std::cout

* clang-format -i -style="{IndentWidth: 4}" queue_using_array.cpp

* Update queue_using_array.cpp

* Update queue_using_array.cpp

* Update queue_using_array.cpp

* Update queue_using_array.cpp

Co-authored-by: Christian Clauss <cclauss@me.com>

data_structure/queue_using_array.cpp

@@ -0,0 +1,93 @@
+/*
+    Write a program to implement Linear Queue using array.
+
+    Functions to implement
+        Enqueue (Insertion)
+        Dequeue (Deletion)
+
+*/
+#include <iostream>
+
+#define MAXSIZE 10
+
+class Queue_Array {
+    int front;
+    int rear;
+    int size;
+
+ public:
+    Queue_Array() {
+        front = -1;
+        rear = -1;
+        size = MAXSIZE;
+    }
+    int *arr = new int[size];
+    void enqueue(int);
+    int dequeue();
+    void display();
+};
+
+void Queue_Array::enqueue(int ele) {
+    if (rear == size - 1) {
+        std::cout << "\nStack is full";
+    } else if (front == -1 && rear == -1) {
+        front = rear = 0;
+        arr[rear] = ele;
+    } else if (rear < size) {
+        rear++;
+        arr[rear] = ele;
+    }
+}
+
+int Queue_Array::dequeue() {
+    int d;
+    if (front == -1) {
+        std::cout << "\nstack is empty ";
+        return 0;
+    } else if (front == rear) {
+        d = arr[front];
+        front = rear = -1;
+    } else {
+        d = arr[front++];
+    }
+
+    return d;
+}
+
+void Queue_Array::display() {
+    if (front == -1) {
+        std::cout << "\nStack is empty";
+    } else {
+        for (int i = front; i <= rear; i++)
+            std::cout << arr[i] << " ";
+    }
+}
+
+int main() {
+    int op, data;
+
+    Queue_Array ob;
+
+    std::cout << "\n1. enqueue(Insertion) ";
+    std::cout << "\n2. dequeue(Deletion)";
+    std::cout << "\n3. Display";
+    std::cout << "\n4. Exit";
+    while (1) {
+        std::cout << "\nEnter your choice ";
+        std::cin >> op;
+        if (op == 1) {
+            std::cout << "Enter data  ";
+            std::cin >> data;
+            ob.enqueue(data);
+        } else if (op == 2) {
+            data = ob.dequeue();
+            std::cout << "\ndequeue element is:\t" << data;
+        } else if (op == 3) {
+            ob.display();
+        } else if (op == 4) {
+            exit(0);
+        } else {
+            std::cout << "\nWrong choice ";
+        }
+    }
+}