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  1. #include <stdio.h>
  2. #include <stdlib.h>
  3.  
  4. #define QUEUE_SIZE 10
  5.  
  6. typedef struct {
  7.   int data[QUEUE_SIZE];
  8.   int number;
  9.   int head;
  10. } QUEUE;
  11.  
  12. QUEUE* create_queue() {
  13.   QUEUE* queue = (QUEUE*)malloc(sizeof(QUEUE));
  14.  
  15.   queue->head = 0;
  16.   queue->number = 0;
  17.   return queue;
  18. }
  19.  
  20. int enqueue(QUEUE* queue, int value) {
  21.   if (queue->number < QUEUE_SIZE){
  22.     queue->data[(queue->head + queue->number) % QUEUE_SIZE] = value;
  23.     queue->number++;
  24.     return 0;
  25.   } else { 
  26.     return -1;
  27.   }
  28. }
  29.  
  30. int dequeue(QUEUE* queue) {
  31.   int r;
  32.   if (queue->number > 0) {
  33.     r = queue->data[queue->head % QUEUE_SIZE];
  34.     queue->head++;
  35.     queue->number--;
  36.   } else {
  37.     r = -1;
  38.   }
  39.   return r;
  40. }
  41.  
  42. int main() {
  43.   QUEUE *q = create_queue();
  44.   printf("<%d\n", enqueue(q, 3));
  45.   printf("<%d\n", enqueue(q, 2));
  46.   printf("<%d\n", enqueue(q, 1));
  47.   printf(":%d\n", dequeue(q));
  48.   printf(":%d\n", dequeue(q));
  49.  
  50.   printf("<%d\n", enqueue(q, 9));
  51.   printf("<%d\n", enqueue(q, 8));
  52.   printf("<%d\n", enqueue(q, 7));
  53.   printf("<%d\n", enqueue(q, 6));
  54.   printf("<%d\n", enqueue(q, 5));
  55.   printf("<%d\n", enqueue(q, 4));
  56.   printf("<%d\n", enqueue(q, 3));
  57.   printf("<%d\n", enqueue(q, 2));
  58.   printf("<%d\n", enqueue(q, 1));
  59.   printf("<%d\n", enqueue(q, 10));
  60.  
  61.   printf(":%d\n", dequeue(q));
  62.   printf(":%d\n", dequeue(q));
  63.   printf(":%d\n", dequeue(q));
  64.   printf(":%d\n", dequeue(q));
  65.   printf(":%d\n", dequeue(q));
  66.   printf(":%d\n", dequeue(q));
  67.   printf(":%d\n", dequeue(q));
  68.   printf(":%d\n", dequeue(q));
  69.   printf(":%d\n", dequeue(q));
  70.   printf(":%d\n", dequeue(q));
  71.   printf(":%d\n", dequeue(q));
  72.   printf(":%d\n", dequeue(q));
  73.  
  74.   free(q);
  75.   return 0;
  76. }
  77. /* end */
  78.  
  79.  
Success #stdin #stdout 0s 4536KB
comments (?)
stdin 
Standard input is empty
stdout 
<0
<0
<0
:3
:2
<0
<0
<0
<0
<0
<0
<0
<0
<0
<-1
:1
:9
:8
:7
:6
:5
:4
:3
:2
:1
:-1
:-1
https://ideone.com/JCwXMp
language:
C (gcc 8.3)
created:
7 years ago
visibility:
public

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