/* Note:Your choice is C IDE */
#include "stdio.h"
#define MAX 100
#include<malloc.h>
typedef int keytype;
typedef struct node
{
    keytype key;
    char data;
    struct node *lchild,*rchild;
}BSTNode;
void displayBST(BSTNode *root);
int insertBST(BSTNode *p,keytype k)
{
    if(!p)
    {
        p=(BSTNode *)malloc(sizeof(BSTNode));
        p->key=k;
        p->lchild=p->rchild=NULL;
        return 1;
    }
    else if(k==p->key)
    return 0;
    else if(k<p->key)
    return insertBST(p->lchild,k);
    else
    return insertBST(p->rchild,k);
}
BSTNode *creatBST(keytype a[],int n)
{
    BSTNode *root=NULL;
    int i=0;
    while(i<n)
    {
        if(insertBST(root,a[i])==1)
        {
            printf("第%d步,插入%d:",i+1,a[i]);
            displayBST(root);printf("\n");
            i++;
        }
    }
    return root;
}
void displayBST(BSTNode *root)
{
    if(root)
    {
        printf("%3d",root->key);
        if(root->lchild||root->rchild)
        {
            
            printf("(");
            displayBST(root->lchild);
            if(root->rchild)
            printf(",");
            displayBST(root->rchild);
            printf(")");
        }
    }
}
void main()
{
    BSTNode *root;
    keytype k=6;
    int a[]={4,9,0,1,8,6,3,5,2,7},n=10;
    printf("创建一颗BST树:\n");
    root=creatBST(a,n);
    printf("BST:");displayBST(root);printf("\n");
   
}
为什么程序运行的时候没有调用输出函数啊！奇怪啊！