Implement Queue using array.cpp

/*
Implement Queue using array
===========================

Implement a Queue using an Array. Queries in the Queue are of the following type:
(i) 1 x   (a query of this type means  pushing 'x' into the queue)
(ii) 2     (a query of this type means to pop element from queue and print the poped element)

Example 1:
Input:
Q = 5
Queries = 1 2 1 3 2 1 4 2
Output: 2 3
Explanation:
In the first test case for query 
1 2 the queue will be {2}
1 3 the queue will be {2 3}
2   poped element will be 2 the 
    queue will be {3}
1 4 the queue will be {3 4}
2   poped element will be 3 

Example 2:
Input:
Q = 4
Queries = 1 3 2 2 1 4   
Output: 3 -1
Explanation:
In the second testcase for query 
1 3 the queue will be {3}
2   poped element will be 3 the
    queue will be empty
2   there is no element in the
    queue and hence -1
1 4 the queue will be {4}. 
Your Task :
You are required to complete the two methods push() which take one argument an integer 'x' to be pushed into the queue and pop() which returns a integer poped out from othe queue. If the queue is empty, it should return -1 on a pop operation. 

Expected Time Complexity: O(1) for both push() and pop().
Expected Auxiliary Space: O(1) for both push() and pop().

Constraints:
1 ≤ Q ≤ 105
1 ≤ x ≤ 105
*/

/* 

The structure of the class is
class MyQueue {
private:
    int arr[100005];
    int front;
    int rear;

public :
    MyQueue(){front=0;rear=0;}
    void push(int);
    int pop();
};
 */

//Function to push an element x in a queue.
void MyQueue ::push(int x)
{
  arr[rear] = x;
  rear++;
}

//Function to pop an element from queue and return that element.
int MyQueue ::pop()
{
  if (rear == front)
    return -1;
  int ans = arr[front];
  front++;
  return ans;
}