Added a cpp program on queue using array and class.

queueusingarray.cpp

@@ -0,0 +1,70 @@
+#include<iostream>
+using namespace std;
+#define n 100
+
+class Queue{
+
+	int* arr;
+	int front;
+	int back;
+
+public:
+	Queue(){
+		arr = new int[n];
+		front = -1;
+		back = -1;
+	}
+
+	void enque(int data){
+		if(back == n-1){
+			cout<<"Queue Overflow"<<endl;
+			return;
+		}
+		back++;
+		arr[back] = data;
+		if(front == -1){
+			front++;
+		}
+	}
+
+	void deque(){
+
+		if(front == -1 || front > back){
+			cout<<"No elements in the queue"<<endl;
+			return;
+		}
+		front++;
+	}
+
+
+	int peek(){
+		if(front == -1 || front > back){
+			cout<<"No elements in the queue"<<endl;
+			return -1;
+		}
+		return arr[front];
+	}
+	void display(){
+		if(front == -1 || front > back){
+			cout<<"No elements in the queue"<<endl;
+			return;
+		}
+		cout<<"The elements are : ";
+		for(int i = front; i <= back; i++){
+			cout<<arr[i]<<" ";
+		}
+		cout<<endl;
+	}
+};
+
+int main(){
+
+	Queue q;
+	q.enque(10);
+	q.enque(20);
+	q.enque(30);
+	q.enque(40);
+	cout<<"Peeked element : " <<q.peek() <<endl;
+
+	q.display();
+}