下面代码为啥会报这样的错？

下面代码为啥会报这样的错？

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BTree.h


#pragma once
#include<stdio.h>
#include<stdlib.h>
#define _CRT_SECURE_NO_WARNINGS
#define MaxSize 1024
//typedef char ElemType;

typedef struct node
{
    char data;
    struct node* lchild;
    struct node* rchild;
}BTNode;

typedef BTNode* ElemType;


typedef struct
{
    ElemType data[MaxSize];
    int top;
}SqStack;

//初始化栈
void InitStack(SqStack*& q);

//销毁栈
void DestroyStack(SqStack*& q);

//判断栈是否为空
bool EmptyStack(SqStack* q);

//进栈
bool Push(SqStack*& q, ElemType e);

//出栈
bool Pop(SqStack*& q, ElemType& e);

//取栈顶元素
bool GetTop(SqStack* q, ElemType& e);

//树
void CreateBT(BTNode*& b, char* str);

void DispBT(BTNode* b);

BTNode* FindNode(BTNode* b, char e);

void DispChild(BTNode* t);

int BTHeight(BTNode* b);

int NodeNum(BTNode* b);

void PreOrder(BTNode* b);

SqStack.cpp


#include"BTree.h"
void InitStack(SqStack*& q)
{
    q->top = -1;
}

void DestroyStack(SqStack*& q)
{
    free(q);
}

bool EmptyStack(SqStack* q)
{
    /*if (q->top == -1)
    {
        return true;
    }
    else
    {
        return false;
    }*/
    return q->top == -1;
}

bool Push(SqStack*& q, ElemType e)//名字都写反
{
    if (q->top == MaxSize - 1)
    {
        return false;
    }
    /*q->top++;
    q->data[q->top] = e;*/
    q->data[++q->top] = e;
    return true;
}

bool Pop(SqStack*& q, ElemType& e)
{
    if (q->top == -1)
    {
        return false;
    }
    /*e = q->data[q->top];
    q->top--;*/
    e = q->data[q->top--];
    return true;
}

bool GetTop(SqStack* q, ElemType& e)
{
    //if (EmptyStack)
    if (EmptyStack(q))
    {
        return false;
    }
    e = q->data[q->top];
    return true;
}

BTree.cpp

#include"BTree.h"

void CreateBT(BTNode*& b, char* str)
{
    BTNode* p = NULL;
    b = NULL;
    BTNode* St[MaxSize];
    int top = -1;
    int k = 0;
    while (*str != '\0')
    {
        switch (*str)
        {
        case '(':
            top++;
            St[top] = p;
            k = 1;
            break;
        case ')':
            top--;
            break;
        case ',':
            k = 2;
            break;
        default:
            p = (BTNode*)malloc(sizeof(BTNode));
            p->data = *str;
            p->lchild = p->rchild = 0;
            if (b == NULL)
            {
                b = p;
            }
            else
            {
                switch (k)
                {
                case 1:
                    St[top]->lchild = p;
                    break;
                case 2:
                    St[top]->rchild = p;
                    break;
                default:
                    break;
                }
            }
            break;
        }
        str++;
    }
}

void DispBT(BTNode* b)
{
    if (b != NULL)
    {
        printf("%c", b->data);
        if (b->lchild != NULL || b->rchild != NULL)
        {
            printf("(");
            DispBT(b->lchild);
            if (b->rchild != NULL)
            {
                printf(",");
            }
            DispBT(b->rchild);
            printf(")");
        }
    }
}

BTNode* FindNode(BTNode* b, char e)
{
    /*BTNode* p = NULL;
    if (b == NULL)
        return NULL;
    if (b->data == e)
    {
        return b;
    }
    p = FindNode(b->lchild, e);
    p = FindNode(b->rchild, e);
    if(p != NULL)
        return p;
    else
        return NULL;*/

    BTNode* p = NULL;
    if (b == NULL)
    {
        return NULL;
    }
    else if (b->data == e)
    {
        p = FindNode(b->lchild, e);
        if (p != NULL)
        {
            return b;
        }
        else
        {
            return FindNode(b->rchild, e);
        }
    }
}

void DispChild(BTNode* t)
{
    printf("%c的左孩子为:%c\n", t->data, t->lchild->data);
    printf("%c的左孩子为:%c\n", t->data, t->rchild->data);
}

//int BTHeight(BTNode* b)
//{
//    int lheight = 0;
//    int rheight = 0;
//    if (b->lchild == NULL && b->rchild == NULL)
//    {
//        return 0;
//    }
//    return (lheight > rheight ? (lheight + 1) : (rheight + 1));
//}

int BTHeight(BTNode* b)
{
    int lheight = 0;
    int rheight = 0;
    if (b == NULL)
    {
        return 0;
    }
    else
    {
        BTHeight(b->lchild);
        BTHeight(b->rchild);
        return (lheight > rheight ? (lheight + 1) : (rheight + 1));
    }
}

int NodeNum(BTNode* b)
{
    if (b == NULL)
    {
        return 0;
    }
    else
    {
        int lnum = NodeNum(b->lchild);
        int rnum = NodeNum(b->rchild);
        return lnum + rnum;
    }
}

void PreOrder(BTNode* b)
{
    //递归方法
    /*if (b != NULL)
    {
        printf("%c", b->data);
        PreOrder(b->lchild);
        PreOrder(b->rchild);
    }*/
    //非递归方法
    BTNode* p;
    SqStack* st;
    InitStack(st);
    if (b != NULL)
    {
        Push(st, b);
        while (!EmptyStack(st))
        {
            Pop(st, p);
            printf("%c", p->data);
            if (p->rchild != NULL)
            {
                Push(st, p->rchild);
            }
            if (p->lchild != NULL)
            {
                Push(st, p->lchild);
            }
        }
        printf("\n");
    }
    DestroyStack(st);
}

你的main入口呢，你在哪里调用了dispBTNode方法