按凹入表形式横向打印二叉树结构c语言代码，用初学者的方法，同时各函数功能相互独立

以下是一个简单的横向打印二叉树结构的C语言代码，各函数功能相互独立。

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

struct TreeNode {
    int val;
    struct TreeNode *left;
    struct TreeNode *right;
};

// 获取二叉树的高度
int getHeight(struct TreeNode* root) {
    if (root == NULL) {
        return 0;
    }
    int leftHeight = getHeight(root->left);
    int rightHeight = getHeight(root->right);
    return leftHeight > rightHeight ? leftHeight + 1 : rightHeight + 1;
}

// 打印空格
void printSpace(int num) {
    for (int i = 0; i < num; i++) {
        printf(" ");
    }
}

// 打印节点值
void printVal(int val) {
    printf("%d", val);
}

// 横向打印二叉树
void printTree(struct TreeNode* root, int level) {
    if (root == NULL) {
        return;
    }
    int height = getHeight(root);
    int spaceNum = 4 * (1 << (height - level - 1)) - 3;
    printTree(root->right, level + 1);
    printSpace(spaceNum / 2);
    printVal(root->val);
    printSpace(spaceNum / 2);
    printTree(root->left, level + 1);
}

int main() {
    // 构建一个二叉树
    struct TreeNode* root = (struct TreeNode*)malloc(sizeof(struct TreeNode));
    root->val = 1;
    root->left = (struct TreeNode*)malloc(sizeof(struct TreeNode));
    root->left->val = 2;
    root->right = (struct TreeNode*)malloc(sizeof(struct TreeNode));
    root->right->val = 3;
    root->left->left = (struct TreeNode*)malloc(sizeof(struct TreeNode));
    root->left->left->val = 4;
    root->left->right = (struct TreeNode*)malloc(sizeof(struct TreeNode));
    root->left->right->val = 5;
    root->right->left = (struct TreeNode*)malloc(sizeof(struct TreeNode));
    root->right->left->val = 6;
    root->right->right = (struct TreeNode*)malloc(sizeof(struct TreeNode));
    root->right->right->val = 7;

    // 横向打印二叉树
    printTree(root, 0);

    // 释放二叉树内存
    free(root->left->left);
    free(root->left->right);
    free(root->right->left);
    free(root->right->right);
    free(root->left);
    free(root->right);
    free(root);

    return 0;
}

上述代码中，getHeight函数用来获取二叉树的高度；printSpace函数用来打印空格；printVal函数用来打印节点值；printTree函数用来横向打印二叉树；main函数则是构建一个二叉树并打印。各函数功能相互独立，可以单独使用。