queue 구현

1. #include <cstdlib>
2. #include <iostream>
3. using namespace std;
4. #define QUEUE_C 8
5. int queue[QUEUE_C];
6. int head = 0;
7. int tail = -1;
8. int queue_size = 0;
9.  
10. void enqueue(int n)
11. {
12. if(queue_size == QUEUE_C){
13. cout << "queue is full \n";
14. return;
15. }
16. tail++;
17. queue_size++;
18. queue[tail]=n;
19. }
20.  
21. int dequeue()
22. {
23. int r;
24. if(queue_size == 0)
25. {
26. cout << "queue is empty\n";
27. return 0;
28. }
29. r = queue[head];
30. head++;
31. queue_size--;
32. return r;
33. }
34. int main()
35. {
36. int number, r;
37. do
38. {
39. cout << "input number : ";
40. cin >> number;
41.  
42. if(number > 0)
43. {
44. enqueue(number);
45. }else if(number == 0){
46. r = dequeue();
47. cout << r << endl;
48. }
49. }while(number>=0);
50. return 0;
51. }