c语言用队列实现二叉树的层次遍历

以下是C语言使用队列实现二叉树的层次遍历的代码：

#include <stdio.h>
#include <stdlib.h>

// 定义二叉树结构体
typedef struct node {
    int data;
    struct node *left;
    struct node *right;
} Node;

// 定义队列结构体
typedef struct queue {
    Node *data;
    struct queue *next;
} Queue;

// 全局变量，指向队列头和尾
Queue *front = NULL, *rear = NULL;

// 入队操作
void enqueue(Node *data) {
    Queue *newNode = (Queue *) malloc(sizeof(Queue));
    newNode->data = data;
    newNode->next = NULL;
    if (rear == NULL) {
        front = rear = newNode;
    } else {
        rear->next = newNode;
        rear = newNode;
    }
}

// 出队操作
Node *dequeue() {
    if (front == NULL) {
        return NULL;
    }
    Node *data = front->data;
    Queue *temp = front;
    if (front == rear) {
        front = rear = NULL;
    } else {
        front = front->next;
    }
    free(temp);
    return data;
}

// 创建二叉树
Node *createTree() {
    int data;
    printf("请输入节点的值（-1表示空节点）：");
    scanf("%d", &data);
    if (data == -1) {
        return NULL;
    }
    Node *node = (Node *) malloc(sizeof(Node));
    node->data = data;
    node->left = createTree();
    node->right = createTree();
    return node;
}

// 层次遍历
void levelOrderTraversal(Node *root) {
    if (root == NULL) {
        return;
    }
    enqueue(root);
    while (front != NULL) {
        Node *node = dequeue();
        printf("%d ", node->data);
        if (node->left != NULL) {
            enqueue(node->left);
        }
        if (node->right != NULL) {
            enqueue(node->right);
        }
    }
}

int main() {
    Node *root = createTree();
    printf("层次遍历结果：");
    levelOrderTraversal(root);
    return 0;
}