C语言二叉查找树

Question

C语言二叉查找树问题，在 return searchBST( T->rchild, val, f, p); 处出错，求教出错原理，这里应该涉及了双重指针的问题，我理不清。#include <stdio.h>#include <malloc.h>#define OK 1#define TRUE 1#define ERROR -1#define FALSE 0typedef int ElemType;typedef struct Node{    ElemType data;    struct Node *lchild,*rchild;}NODE,*PNODE;//prompt error info and exit.void errorInfo(char str[]){    printf("%s\n",str);    exit(-1);}//prompt error if there is an error in locating memoryvoid mallocErr(PNODE p){    if(NULL==p)        errorInfo("Error in locating memory.");}//search binary sort treeint searchBST(PNODE T,int val,PNODE *f,PNODE *p){    if(!T)    {        *p = *f;        return FALSE;    }    else if(val == T->data)    {        *p = T;        return TRUE;    }else if(val < T->data)    {        printf("run this code 52\n");        *f = T;        return searchBST(T->lchild,val,f,p);    }else    {        printf("run this code 56\n");        *f = T;        printf("run this code 58\n");        printf("T->data : %d \n",T->data);        //运行到此处出错        return searchBST( T->rchild, val, f, p);    }}int insertBST(PNODE *T,int val){    PNODE p = NULL, s = NULL,f = NULL;    int res = 0;    res = searchBST(*T,val,&f,&p);    if(!res) //val does not exist in the array.    {        s = (PNODE)malloc(sizeof(NODE));        mallocErr(s);        s->data = val;        if(!p) //p is null        {            printf("run this code 75\n");            printf("Create Tree with val:%d\n",val);            *T = s;        }else if(val < p->data)        {            printf("run this code 79\n");            printf("Insert Key To Tree(left):%d\n",val);            p->lchild = s;        }else        {            printf("run this code 84\n");            printf("Insert Key To Tree(right):%d\n",val);            p->rchild = s;        }        return TRUE;    }else   //val already exists in the array.    {        return FALSE;    }}int main(){    PNODE T = NULL, p = NULL;    insertBST(&T,100);    insertBST(&T,199);    return 0;}

Answer 1

建议你直接问老师，然后再自己整理一遍。