c语言列队怎样实现先进先出

在C语言中，实现队列的先进先出（FIFO）可以通过结构体、数组和链表三种数据结构来实现。这里我将分别介绍这三种方法：

1. 使用结构体实现队列：

#include <stdio.h> #include <stdlib.h>  typedef struct {     int *data;     int front;     int rear;     int size;     int capacity; } Queue;  Queue* createQueue(int capacity) {     Queue* queue = (Queue*)malloc(sizeof(Queue));     queue->capacity = capacity;     queue->front = queue->size = 0;     queue->rear = capacity - 1;     queue->data = (int*)malloc(queue->capacity * sizeof(int));     return queue; }  int isFull(Queue* queue) {     return (queue->size == queue->capacity); }  int isEmpty(Queue* queue) {     return (queue->size == 0); }  void enqueue(Queue* queue, int item) {     if (isFull(queue))         return;     queue->rear = (queue->rear + 1) % queue->capacity;     queue->data[queue->rear] = item;     queue->size = queue->size + 1; }  int dequeue(Queue* queue) {     if (isEmpty(queue))         return -1;     int item = queue->data[queue->front];     queue->front = (queue->front + 1) % queue->capacity;     queue->size = queue->size - 1;     return item; }  int main() {     Queue* queue = createQueue(5);     enqueue(queue, 10);     enqueue(queue, 20);     enqueue(queue, 30);     enqueue(queue, 40);     enqueue(queue, 50);      while (!isEmpty(queue)) {         printf("%d ", dequeue(queue));     }      free(queue->data);     free(queue);     return 0; } 

2. 使用数组实现队列：

#include <stdio.h> #include <stdlib.h>  typedef struct {     int *array;     int front;     int rear;     int size;     int capacity; } QueueArray;  QueueArray* createQueueArray(int capacity) {     QueueArray* queue = (QueueArray*)malloc(sizeof(QueueArray));     queue->capacity = capacity;     queue->front = queue->size = 0;     queue->rear = capacity - 1;     queue->array = (int*)malloc(queue->capacity * sizeof(int));     return queue; }  int isFull(QueueArray* queue) {     return (queue->size == queue->capacity); }  int isEmpty(QueueArray* queue) {     return (queue->size == 0); }  void enqueue(QueueArray* queue, int item) {     if (isFull(queue))         return;     queue->rear = (queue->rear + 1) % queue->capacity;     queue->array[queue->rear] = item;     queue->size = queue->size + 1; }  int dequeue(QueueArray* queue) {     if (isEmpty(queue))         return -1;     int item = queue->array[queue->front];     queue->front = (queue->front + 1) % queue->capacity;     queue->size = queue->size - 1;     return item; }  int main() {     QueueArray* queue = createQueueArray(5);     enqueue(queue, 10);     enqueue(queue, 20);     enqueue(queue, 30);     enqueue(queue, 40);     enqueue(queue, 50);      while (!isEmpty(queue)) {         printf("%d ", dequeue(queue));     }      free(queue->array);     free(queue);     return 0; } 

3. 使用链表实现队列：

#include <stdio.h> #include <stdlib.h>  typedef struct Node {     int data;     struct Node* next; } Node;  typedef struct Queue {     Node* front;     Node* rear;     int size; } QueueLinkedList;  QueueLinkedList* createQueue() {     QueueLinkedList* queue = (QueueLinkedList*)malloc(sizeof(QueueLinkedList));     queue->front = queue->rear = NULL;     queue->size = 0;     return queue; }  void enqueue(QueueLinkedList* queue, int item) {     Node* newNode = (Node*)malloc(sizeof(Node));     newNode->data = item;     newNode->next = NULL;      if (queue->rear == NULL) {         queue->front = queue->rear = newNode;         return;     }      queue->rear->next = newNode;     queue->rear = newNode; }  int dequeue(QueueLinkedList* queue) {     if (queue->front == NULL)         return -1;      Node* temp = queue->front;     int item = temp->data;     queue->front = queue->front->next;      if (queue->front == NULL)         queue->rear = NULL;      free(temp);     queue->size = queue->size - 1;     return item; }  int main() {     QueueLinkedList* queue = createQueue();     enqueue(queue, 10);     enqueue(queue, 20);     enqueue(queue, 30);     enqueue(queue, 40);     enqueue(queue, 50);      while (!isEmpty(queue)) {         printf("%d ", dequeue(queue));     }      return 0; } 

以上三种方法都可以实现队列的先进先出（FIFO）。