C++ Queue Exercises: Find the median of all elements of the said queue

C++ Queue: Exercise-6 with Solution

Write a C++ program to find the median of all elements of a queue.

Sample Solution:

C Code:

#include <iostream>
#include <stack>

using namespace std;

const int MAX_SIZE = 100;

class Queue {
  private:
    int front; // Front index of the queue
    int rear; // Rear index of the queue
    int arr[MAX_SIZE]; // Array to store elements

  public:
    Queue() {
      front = -1; // Initialize front index to -1
      rear = -1; // Initialize rear index to -1
    }

    bool isFull() {
      return (rear == MAX_SIZE - 1); // Check if the queue is full
    }

    bool isEmpty() {
      return (front == -1 && rear == -1); // Check if the queue is empty
    }

    void enqueue(int x) {
      if (isFull()) {
        cout << "Error: Queue is full" << endl; // Display error message if queue is full
        return;
      }
      if (isEmpty()) {
        front = 0;
        rear = 0;
      } else {
        rear++;
      }
      arr[rear] = x; // Insert the element at the rear index
    }

    void dequeue() {
      if (isEmpty()) {
        cout << "Error: Queue is empty" << endl; // Display error message if queue is empty
        return;
      }
      if (front == rear) {
        front = -1;
        rear = -1;
      } else {
        front++;
      }
    }

    int peek() {
      if (isEmpty()) {
        cout << "Error: Queue is empty" << endl; // Display error message if queue is empty
        return -1;
      }
      return arr[front]; // Return the element at the front of the queue
    }

    void display() {
      if (isEmpty()) {
        cout << "Error: Queue is empty" << endl; // Display error message if queue is empty
        return;
      }
      cout << "Queue elements are: ";
      for (int i = front; i <= rear; i++) {
        cout << arr[i] << " "; // Display all elements in the queue
      }
      cout << endl;
    }

    // Function to calculate the median of elements in the queue
    float median_Queue(Queue & q) {
      if (q.isEmpty()) {
        cout << "Error: Queue is empty" << endl; // Display error message if queue is empty
        return 0.0;
      }
      int count = 0;
      int mid = 0;
      for (int i = q.front; i <= q.rear; i++) {
        count++; // Count the number of elements
      }
      mid = count / 2; // Calculate the middle index

      if (count % 2 == 0) {
        // If the count is even, calculate the average of two middle elements
        float median = static_cast < float > (q.arr[q.front + mid] + q.arr[q.front + mid - 1]) / 2;
        return median;
      } else {
        // If the count is odd, return the middle element
        float median = q.arr[q.front + mid];
        return median;
      }
    }
};

int main() {
  cout << "Initialize a Queue." << endl;
  Queue q;
  cout << "\nInsert some elements into the queue:" << endl;
  q.enqueue(1);
  q.enqueue(2);
  q.enqueue(3);
  q.enqueue(4);
  q.enqueue(5);
  q.display();

  // Calculate and display the median of elements in the queue
  float med_val = q.median_Queue(q);
  cout << "Find the median of all elements of the said queue: " << med_val;

  cout << "\n\nInput one more element into the queue:" << endl;
  q.enqueue(6);
  q.display();

  // Calculate and display the median of elements in the queue after adding a new element
  med_val = q.median_Queue(q);
  cout << "Find the median of all elements of the said queue: " << med_val;

  return 0;
}

Sample Output:

Initialize a Queue.

Insert some elements into the queue:
Queue elements are: 1 2 3 4 5 
Find the median of all elements of the said queue: 3

Input one more element into the queue:
Queue elements are: 1 2 3 4 5 6 
Find the median of all elements of the said queue: 3.5

Flowchart:

CPP Code Editor:

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Previous C++ Exercise: Find the average of all elements of a queue.
Next C++ Exercise: Find the mode of all elements of a queue.