一步一步复习数据机构和算法基础-二叉树创建（前序建立二叉树）

来源：互联网发布：mac六国语言编辑：程序博客网时间：2024/06/09 22:45

最基础的二叉树：

#include <stdio.h>#include <stdlib.h>typedef int elemtype;//整形为树的数据类型typedef struct node{elemtype data;struct node *lchild,*rchild;}btree,*ptree;void (*visit)(elemtype e);//树的创建ptree CreatTree(){ptree root;elemtype data;scanf("%d",&data);if(data == 0)root = NULL;//0 代表空子树else{root = (ptree)malloc(sizeof(btree));if(!root)exit(1);root->data = data;root->lchild = CreatTree();root->rchild = CreatTree();}return root;}void PrintResult(elemtype e){printf("%d ",e);}//前序遍历二叉树void PreOrderTree(ptree root,void (*visit)(elemtype )){if(root){(visit)(root->data);PreOrderTree(root->lchild,visit);PreOrderTree(root->rchild,visit);}}//中序遍历二叉树void InOrderTree(ptree root,void (*visit)(elemtype )){if(root){PreOrderTree(root->lchild,visit);(visit)(root->data);PreOrderTree(root->rchild,visit);}}//后序遍历二叉树void PostOrderTree(ptree root,void (*visit)(elemtype )){if(root){PreOrderTree(root->lchild,visit);PreOrderTree(root->rchild,visit);(visit)(root->data);}}int main(){ptree root = NULL;root = CreatTree();PreOrderTree(root,PrintResult);printf("\n");InOrderTree(root,PrintResult);printf("\n");PostOrderTree(root,PrintResult);printf("\n");return 0;}

不过二叉树的建立方式各异，下面是第二种二叉树的建立方式

#include<stdio.h>#include<stdlib.h>#include<string.h>#define maxitem 1024#define ok 1typedef char elemtype;typedef struct BiTNode{elemtype data;struct BiTNode *lchild,*rchild;}bitnode,*bitree;//初始化树根节点int init(bitree *t){*t = NULL;return ok;}//前序创建二叉树int creat(bitree *t){char ch;scanf("%c",&ch);if (ch == '#')*t = NULL;else{*t = (bitree)malloc(sizeof(bitnode));if (!*t)exit(1);(*t)->data = ch;creat(&(*t)->lchild);creat(&(*t)->rchild);}return 1;}//前序遍历二叉树void InOrderTraverse(bitree T){if(T){InOrderTraverse(T->lchild);InOrderTraverse(T->rchild);printf("%c",T->data);}}int main(){bitree t;init(&t);creat(&t);InOrderTraverse(t);printf("\n");return 0;}