Btree Visual Print

Introduction

二叉树动态可视化打印，纯C实现。这么基础的东西网上竟然没有，于是我造了一个，这对于学习数据结构和算法来说还是有用的。

Print binary tree visually, using pure c. Since I haven't find similar programs on the Internet, I build one, which is quite convenient for learning data structures and algorithms.

Preview

  _(5)___
  |      |
 (2)  _(10)__________
      |              |
     (5)       ____(20)
               |
            _(17)_
            |     |
          (12)  (19)

// 下面这颗树可能有点宽 :-)
// below tree is a little wider :-)


                    _______________________________(Amy)_____________________
                    |                                                        |
               ___(Bob)____________________                            ___(Carl)___________________
               |                           |                           |                           |
    ________(David)            ________(Edison)__                ___(Frank)             _______(George)__
    |                          |                 |               |                      |                |
 (Henry)__               ___(Iris)__          (Jack)       ___(Kevin)             ___(Laura)_         (Mark)_
          |              |          |                      |                      |          |               |
       (Neil)         (Oscar)    (Peter)               (Queena)                (Robin)     (Sam)           (Tom)

Usage

For macro:

你的二叉树结点必须看起来像下面的定义，但不必完全一致。

Your binary tree's node should look like this, but it needn't be the very same.

typedef struct node
{
    char data;
    struct node *lchild, *rchild;
} BTNode, *BTree;

然后 then

#include "btree_visual_print_macro.h"

BTree t1;

/* add some contents to t1 */

BTREE_VISUAL_PRINT(BTree, t1, lchild, rchild, data, "%c", stdout);

/* where %c is the format str of the element in each node */

For function:

你的二叉树结点必须使用下面的定义，或在进入.h文件，在函数中替换成你的定义。

Your binary tree's node should be exact this, or replace the definition in .h file with yours.

typedef struct node
{
    char data;
    struct node *lchild, *rchild;
} BTNode, *BTree;

然后 then

#include "btree_visual_print.h"

BTree t1;

/* add some contents to t1 */

btree_visual_print(t, "%d", stdout);

/* where %d is the format str of the element in each node */

Other things

• 支持char、int、char*、double等基本类型 Supported types are: char, int, char*, double, among other basic types
• 其他类型（如指针、结构体）可能要修改两行代码，已用TODO标出 For other types such as ptr or struct, two lines of code should be altered, which are marked as TODO in the code
• 单个元素的字符长度最长为128，可以修改 The max length of the str of each element is 128, which can be modified

Theory

• 中序遍历计算横坐标 In-order to calculate the horizontal coordinate
• 层序遍历计算纵坐标 Layer-order to calculate the vertical coordinate
• sprintf预先求字符串长度，而不是itoa Use sprintf instead of itoa to pre-calculate str length
• 剩下的自己看吧，懒得写了╮(╯-╰)╭ Read the remnant by yourself, as I'm so lazy ╮(╯-╰)╭