创建二叉排序树，先序遍历，中序遍历，判断是否存在关键点

这是所要创建的二叉排序树，a[10] = {4, 5, 2, 1, 0, 9, 3, 7, 6, 8}，请先在草稿纸上画出图形，再看程序

代码实现：

#include <stdio.h>#include <stdlib.h>typedef struct BTNode{int key,cout;struct BTNode *lchild;struct BTNode *rchild;}BTNode;//创建二叉排序树 bool BSTInsert(BTNode *&bt,int x){if(bt==NULL){bt=(BTNode*)malloc(sizeof(BTNode));bt->key=x;bt->lchild=bt->rchild=NULL;return true;}if(x==bt->key)return false; if(x>bt->key)return BSTInsert(bt->rchild,x); elsereturn BSTInsert(bt->lchild,x);}//先序遍历 void PreOrderTraverse(BTNode *bt){if(bt){printf("%d ",bt->key);PreOrderTraverse(bt->lchild);PreOrderTraverse(bt->rchild);}}//中序遍历 void InOrderTraverse(BTNode *bt){if(bt){InOrderTraverse(bt->lchild);printf("%d ",bt->key);InOrderTraverse(bt->rchild);}}//查找关键点是否存在 bool BSTSearch(BTNode *bt,int x){//找到关键字返回1，否则返回0 if(!bt){return 0;}else{if(bt->key==x)return 1;else if(bt->key>x)return BSTSearch(bt->lchild,x);elsereturn BSTSearch(bt->rchild,x);}}int main(int argc, char *argv[]){int i,a[10] = {4, 5, 2, 1, 0, 9, 3, 7, 6, 8}; struct BTNode *bt=NULL;for(i=0;i<10;++i){BSTInsert(bt,a[i]);}printf("%d\n",BSTSearch(bt,6));printf("先序遍历："); PreOrderTraverse(bt);printf("\n中序遍历：");InOrderTraverse(bt); printf("\n");return 0;}

输出结果：

1先序遍历：4 2 1 0 3 5 9 7 6 8中序遍历：0 1 2 3 4 5 6 7 8 9请按任意键继续. . .