数据结构-树

对于树的数据结构中我感觉最大的难点就属递归了，递归的思想说起貌似很好懂，但是，如果写的话还是似会非会，此处需要加强学习。

//  main.c
//  treee
//
//  Created by harrytc on 2018/10/7.
//  Copyright © 2018年 harrytc. All rights reserved.
//

#include <stdio.h>
# include <stdlib.h>
#define maxSize 100
typedef struct BTNode
{
    char data;
    struct BTNode * lchild;
    struct BTNode * rchild;
}BTNode;



void Visit(BTNode *p)
{
    
}

int getDepth (BTNode * p)
{
    int LD,RD;
    if (p == NULL)
        return 0;
    else
    {
        LD = getDepth(p->lchild);
        RD = getDepth(p->rchild);
        return (LD > RD ? LD : RD) + 1;
    }
}

void trave (BTNode * p, int k)
{
    int n = 0;
    if (p != NULL)
    {
        ++n;
        if (k == n)
        {
            printf("%c \n",p->data);
        }
        return;
    }
    trave(p->lchild, k);
    trave(p->rchild, k);
}

void preorder(BTNode *p) /*前序递归遍历*/
{
    if(p != NULL)
    {
        Visit(p);
        preorder(p->lchild);
        preorder(p->rchild);
    }
}

void preorderNonrecursion(BTNode *bt) /*前序非递归遍历*/
{
    BTNode * Stack[maxSize];
    int top = -1;
    BTNode * p;
    Stack[++top] = bt;
    while(top != -1)
    {
        p = Stack[top--];
        Visit(p);
        if (p->rchild != NULL)
            Stack[top++] = p->rchild;
        if (p->lchild != NULL)
            Stack[top--] = p->lchild;
    }
}

void inorder(BTNode * p)    /*中序遍历*/
{
    if(p != NULL)
    {
        inorder(p->lchild);
        Visit(p);
        inorder(p->rchild);
    }
}



void postorder(BTNode * p)    /*后序遍历*/
{
    if (p != NULL)
    {
        postorder(p->lchild);
        postorder(p->rchild);
        Visit(p);
    }
}



int main(int argc, char *argv[])
{
    struct BTNode * pA = (struct BTNode *)malloc(sizeof(struct BTNode));
    struct BTNode * pB = (struct BTNode *)malloc(sizeof(struct BTNode));
    struct BTNode * pC = (struct BTNode *)malloc(sizeof(struct BTNode));
    struct BTNode * pD = (struct BTNode *)malloc(sizeof(struct BTNode));
    struct BTNode * pE = (struct BTNode *)malloc(sizeof(struct BTNode));
    
    pA->data = 'A';
    pB->data = 'B';
    pC->data = 'C';
    pD->data = 'D';
    pE->data = 'E';
    
    pA->lchild = pB;
    pA->rchild = pC;
    pB->lchild = pB->rchild = NULL;
    pC->lchild = pD;
    pC->rchild = NULL;
    pD->lchild = NULL;
    pD->rchild = pE;
    pE->lchild = pE->rchild = NULL;
    printf("%d \n", getDepth(pA));
    
}

最近比较忙，晚些时候会把注释补详细