C语言实现完全二叉树的层序遍历

以下是C语言实现完全二叉树的层序遍历的代码示例：

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

// 定义二叉树结构体
typedef struct TreeNode {
    int val;
    struct TreeNode *left;
    struct TreeNode *right;
} TreeNode;

// 定义队列结构体
typedef struct Queue {
    TreeNode **data;
    int front, rear, size;
} Queue;

// 初始化队列
Queue *initQueue(int size) {
    Queue *q = (Queue *)malloc(sizeof(Queue));
    q->data = (TreeNode **)malloc(sizeof(TreeNode *) * size);
    q->front = q->rear = 0;
    q->size = size;
    return q;
}

// 判断队列是否为空
int isEmpty(Queue *q) {
    return q->front == q->rear;
}

// 入队
void enQueue(Queue *q, TreeNode *node) {
    if (q == NULL || node == NULL) {
        return;
    }
    q->data[q->rear++] = node;
}

// 出队
TreeNode *deQueue(Queue *q) {
    if (q == NULL || isEmpty(q)) {
        return NULL;
    }
    return q->data[q->front++];
}

// 层序遍历
void levelOrder(TreeNode *root) {
    if (root == NULL) {
        return;
    }
    Queue *q = initQueue(100);
    enQueue(q, root);
    while (!isEmpty(q)) {
        TreeNode *node = deQueue(q);
        printf("%d ", node->val);
        if (node->left != NULL) {
            enQueue(q, node->left);
        }
        if (node->right != NULL) {
            enQueue(q, node->right);
        }
    }
}

// 创建二叉树
TreeNode *createTree(int *a, int i, int n) {
    if (i >= n || a[i] == 0) {
        return NULL;
    }
    TreeNode *root = (TreeNode *)malloc(sizeof(TreeNode));
    root->val = a[i];
    root->left = createTree(a, 2 * i + 1, n);
    root->right = createTree(a, 2 * i + 2, n);
    return root;
}

int main() {
    int a[] = {1, 2, 3, 4, 5, 6, 7};
    int n = sizeof(a) / sizeof(int);
    TreeNode *root = createTree(a, 0, n);
    levelOrder(root); // 输出：1 2 3 4 5 6 7
    return 0;
}