环境：VS2019 C语言

问题：根据传入函数的参数和返回值输出二维数组内的所有元素的方法。

程序目的：实现二叉树的层序遍历

函数如下：

int** LevelOrder(struct TreeNode *root,int *returnSize,int** returnColumnSizes){
	*returnSize = 0;
	if (root == NULL) {
		return NULL;
	}
	int** res =(int**)malloc(sizeof(int*) * 1000);
	*returnColumnSizes =(int*)malloc(sizeof(int)*1000);
	if (!res || !*returnColumnSizes)
		return NULL;
	struct TreeNode* queue[1000];
	int front = -1, rear = -1;
	queue[++rear] = root;
	while (rear != front) {
		(*returnColumnSizes)[*returnSize] = rear - front;
		res[*returnSize] =(int*)malloc(sizeof(int)*(rear-front));
		if (res[*returnSize] == NULL) return NULL;
		for (int i = 0, j = front + 1; i < rear - front;i++,j++){
			res[*returnSize][i] = queue[j]->val;
		}
		(*returnSize)++;
		int tmp = rear;
		for (int i = front + 1; i <= tmp;i++) {
			if (queue[i]->left) {
				queue[++rear] = queue[i]->left;
			}
			if (queue[i]->right) {
				queue[++rear] = queue[i]->right;
			}
		}
		front = tmp;
	}
	return res;
}

#include<malloc.h>
#include<stdio.h>
typedef struct TreeNode {
	int val;
	struct TreeNode* left;
	struct TreeNode* right;
}BiTnode;
void CreateBiTree(BiTnode** root) {
	if (*root == NULL) return;
	int value = -1;
	scanf_s("%d", &value);
	if (value == -1) {
		*root = NULL;
	}
	else {
		*root =(BiTnode*)malloc(sizeof(BiTnode));
		if (*root == NULL) return;
		(*root)->val = value;
		printf("左子树：\n");
		CreateBiTree(&(*root)->left);
		printf("右子树：\n");
		CreateBiTree(&(*root)->right);
	}
}
int** LevelOrder(struct TreeNode *root,int *returnSize,int** returnColumnSizes){
	*returnSize = 0;
	if (root == NULL) {
		return NULL;
	}
	/***
	*returnSize返回输出的数目
    **returnColumnSizes每层的结点数
	***/
	int** res =(int**)malloc(sizeof(int*) * 1000);
	*returnColumnSizes =(int*)malloc(sizeof(int)*1000);
	if (!res || !*returnColumnSizes)
		return NULL;
	struct TreeNode* queue[1000];
	int front = -1, rear = -1;
	queue[++rear] = root;
	while (rear != front) {
		/***
		当前层的结点数
		***/
		(*returnColumnSizes)[*returnSize] = rear - front;
		res[*returnSize] =(int*)malloc(sizeof(int)*(rear-front));
		if (res[*returnSize] == NULL) return NULL;
		for (int i = 0, j = front + 1; i < rear - front;i++,j++){
			/***
			把这一层的节点值放入结果数组中
			***/
			res[*returnSize][i] = queue[j]->val;
		}
		(*returnSize)++;
		int tmp = rear;
		for (int i = front + 1; i <= tmp;i++) {
			if (queue[i]->left) {
				queue[++rear] = queue[i]->left;
			}
			if (queue[i]->right) {
				queue[++rear] = queue[i]->right;
			}
		}
		front = tmp;
	}
	return res;
}
int main() {
	BiTnode *root;
	int returnSize;
	int* returnColumnSize;
	int** res;
	CreateBiTree(&root);
	res=LevelOrder(root, &returnSize, &returnColumnSize);
	for (int i = 0; i < returnSize; i++) {
		printf("%d ", res[returnSize]);
	}
	return 0;
}