Practice Top 30 C++ Programming Questions on Queue

Practice Top 30 C++ Programming Questions on Queue

Q1. Write a program to implement a queue using the std::queue library. Perform the following operations:
1. Insert the integers 10, 20, and 30 into the queue.
2. Remove the front element.
3. Display the front element and the size of the queue.

Expected Output:
Front element: 20
Queue size: 2

Q2. Write a program to create an empty queue and check whether it is empty. Then, add one element to the queue and check again.

Expected Output:
Queue is empty: Yes
Queue is empty after adding an element: No

Q3. Write a program to reverse the elements of a queue. Use the std::queue library and std::stack to reverse the order of elements.

Input:
Elements in queue: 1, 2, 3, 4, 5

Expected Output:
Queue after reversing: 5 4 3 2 1

Q4. Write a program to manage a queue of strings. Add three names (Alice, Bob, and Charlie) to the queue, remove one, and display the remaining elements.

Input:
No input is required.

Expected Output:
Remaining names in queue: Bob Charlie

Q5. Write a program to calculate the sum of all integers in a queue.

Input:
Elements in queue: 4, 7, 1, 8

Expected Output:
Sum of elements: 20

Q6. Write a program to insert elements 5, 10, 15 into a queue. Remove two elements and display the size of the queue.

Input:  
No input is required.  

Expected Output:  
Queue size: 1

Q7. Write a program to peek at the front and back elements of a queue. Insert 10, 20, 30 into the queue.

Input:  
No input is required.  

Expected Output:  
Front element: 10  
Back element: 30

Q8. Write a program to merge two queues into one.  
Queue 1: 1, 2, 3  
Queue 2: 4, 5, 6

Expected Output:  
Merged queue: 1 2 3 4 5 6

Q9. Write a program to count the number of even numbers in a queue.  
Queue: 3, 6, 8, 5, 10

Expected Output:  
Number of even elements: 3

Q10. Write a program to check if a specific element exists in a queue.  
Queue: 12, 24, 36, 48  
Check for 24.

Expected Output:  
Element 24 is in the queue.

Q11. Write a program to continuously add numbers to a queue until the user inputs 0. Display all elements.

Input:  
4 7 9 0  

Expected Output:  
Queue: 4 7 9

Q12. Write a program to find the maximum element in a queue.  
Queue: 3, 15, 7, 10, 25

Expected Output:  
Maximum element: 25

Q13. Write a program to find the minimum element in a queue.  
Queue: 8, 4, 11, 2, 9

Expected Output:  
Minimum element: 2

Q14. Write a program to print the queue in reverse order without modifying it.  
Queue: 3, 6, 9, 12

Expected Output:  
Reverse order: 12 9 6 3

Q15. Write a program to display alternate elements of a queue.  
Queue: 5, 10, 15, 20, 25

Expected Output:  
Alternate elements: 5 15 25

Q16. Write a program to check if a queue forms a palindrome sequence.  
Queue: 1, 2, 3, 2, 1

Expected Output:  
The queue forms a palindrome.

Q17. Simulate a circular queue using the std::deque library. Insert 10, 20, 30, remove one element, and add 40.

Expected Output:  
Queue: 20 30 40

Q18. Interleave the elements of two queues.  
Queue 1: 1, 3, 5  
Queue 2: 2, 4, 6

Expected Output:  
Interleaved queue: 1 2 3 4 5 6

Q19. Write a program to reverse the first n elements of a queue.  
Queue: 10, 20, 30, 40, 50  
n = 3

Expected Output:  
Queue after reversing first 3 elements: 30 20 10 40 50

Q20. Write a program to manage a queue of characters. Insert A, B, C, D, remove two, and display the remaining elements.

Expected Output:  
Queue: C D

Q21. Sort the elements of a queue in ascending order.  
Queue: 5, 2, 8, 1, 3

Expected Output:  
Sorted queue: 1 2 3 5 8

Q22. Implement a priority queue using std::priority_queue. Insert 5, 3, 8, 1 and display the elements.

Expected Output:  
Priority queue: 8 5 3 1

Q23. Write a program to double all the elements in a queue.  
Queue: 2, 4, 6, 8

Expected Output:  
Updated queue: 4 8 12 16

Q24. Find the second largest element in a queue.  
Queue: 12, 45, 7, 10, 30

Expected Output:  
Second largest element: 30

Q25. Calculate the sum of all odd numbers in a queue.  
Queue: 1, 4, 5, 6, 9

Expected Output:  
Sum of odd elements: 15

Q26. Write a recursive function to display all elements of a queue.  
Queue: 7, 14, 21

Expected Output:  
Queue: 7 14 21

Q27. Write a program to copy the contents of one queue into another.  
Queue: 10, 20, 30

Expected Output:  
Copied queue: 10 20 30

Q28. Simulate a queue with a fixed size limit. Insert elements until the limit is reached.  
Limit: 3  
Elements: 10, 20, 30, 40

Expected Output:  
Queue is full. Cannot insert 40.

Q29. Write a program to remove duplicate elements from a queue.  
Queue: 10, 20, 10, 30, 20

Expected Output:  
Queue after removing duplicates: 10 20 30

Q30. Use a queue to generate the first n Fibonacci numbers.  
Input n = 5

Expected Output:  
Fibonacci sequence: 0 1 1 2 3