c - 错误: ‘node’ undeclared (first use in this function)

Question

编译时出现此错误

queue.c: In function ‘enqueue’:
queue.c:25:10: error: ‘node’ undeclared (first use in this function)
queue.c:25:10: note: each undeclared identifier is reported only once for each function it appears in

为什么会出现这个？我不明白如何定义变量节点。

这是我的排队代码:

   void enqueue(Queue* queue, int value){
      QNode* node =(QNode *)malloc(sizeof(struct QNode));
      node->data = value;
      if(queue->size == 0){
        q->front = node;
        q->rear = node;
      }else{
        queue->rear->next = node;
        queue->rear = node;
        queue->size++;
      }
}

在文件的开头，我这样定义QNode和Queue:

typedef struct QNode;
struct QNode{
  struct QNode* next;
  int data;
} QNode;

typedef struct Queue{
  int size;
  struct QNode* front;
  struct QNode* rear;
} Queue;

Answer 1

虽然从技术上来说并不是一个错误:

typedef struct QNode;
struct QNode{
  ...

最好写成:

typedef struct QNode {
    ...

您还拥有:

if(queue->size == 0){
        q->front = node;
        q->rear = node;

q 在哪里定义的？

也许你的意思是:

if(queue->size == 0){
        queue->front = node;
        queue->rear = node;