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  1. #include <bits/stdc++.h>
  2. using namespace std;
  3.  
  4. class Queue {
  5. public:
  6.     int front, rear, size;
  7.     unsigned cap;
  8.     int* arr;
  9. };
  10.  
  11. Queue* createQueue(int cap)
  12. {
  13.     Queue* queue = new Queue();
  14.     queue->cap = cap;
  15.     queue->front = queue->size = 0;
  16.  
  17.     queue->rear = cap - 1;
  18.     queue->arr = new int[(queue->cap * sizeof(int))];
  19.     return queue;
  20. }
  21.  
  22. int isFull(Queue* queue)
  23. {
  24.     return (queue->size == queue->cap);
  25. }
  26.  
  27. int isempty(Queue* queue) { return (queue->size == 0); }
  28.  
  29.  
  30. void enqueue(Queue* queue, int item)
  31. {
  32.     if (isFull(queue))
  33.         return;
  34.     queue->rear = (queue->rear + 1) % queue->cap;
  35.     queue->arr[queue->rear] = item;
  36.     queue->size = queue->size + 1;
  37.     cout << item << " enqueued to queue\n";
  38. }
  39.  
  40. int dequeue(Queue* queue)
  41. {
  42.     if (isempty(queue))
  43.         return INT_MIN;
  44.     int item = queue->arr[queue->front];
  45.     queue->front = (queue->front + 1) % queue->cap;
  46.     queue->size = queue->size - 1;
  47.     return item;
  48. }
  49. int front(Queue* queue)
  50. {
  51.     if (isempty(queue))
  52.         return INT_MIN;
  53.     return queue->arr[queue->front];
  54. }
  55. int rear(Queue* queue)
  56. {
  57.     if (isempty(queue))
  58.         return INT_MIN;
  59.     return queue->arr[queue->rear];
  60. }
  61.  
  62.  
  63. int main()
  64. {
  65.     Queue* queue = createQueue(1000);
  66.     enqueue(queue, 10);
  67.     enqueue(queue, 20);
  68.     enqueue(queue, 30);
  69.     enqueue(queue, 40);
  70.     cout << dequeue(queue);
  71.     cout << " dequeued from queue\n";
  72.     cout << "Front item is " << front(queue) << endl;
  73.     cout << "Rear item is " << rear(queue);
  74.     return 0;
  75. }
  76.  
Success #stdin #stdout 0.01s 5288KB
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stdin
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Standard input is empty
stdout
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10 enqueued to queue
20 enqueued to queue
30 enqueued to queue
40 enqueued to queue
10 dequeued from queue
Front item is 20
Rear item is 40
https://ideone.com/GArNGn
language:
C++ (gcc 8.3)
created:
13 hours ago
visibility:
public

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