#include"stdio.h"
#include"malloc.h"
#define ERROR 0
#define OK 0
#define    STACKINCREMENT 5
typedef int status;

typedef struct List
{
    char *base;
    int length;
    int listsize;
}List;

typedef struct BiTree
{
    BiTree *lchild;
    BiTree *rchild;
    char data;
}BiTree, *BiTreeP;

typedef struct stack
{
    BiTreeP *base;
    BiTreeP *top;
    int stacksize;
}stack;

status InitList(List *l)
{
    if(!(l = (List*)malloc(sizeof(List)))) return ERROR;
    l->base = NULL;
    l->length = 0;
    l->listsize = 0;
}

status scandata(List *l,int n)
{
    if(!(l->base = (char*)malloc(n*sizeof(char)))) return ERROR;//程序卡在这一行，给出的错误对话框是:"
    char *p = l->base;                                          //Unhandled exception at 0x00f61497 in BiTree.exe: 0xC0000005:
    while(p)                                                    //Access violation writing location 0x00000000."
    {
        scanf("%d",p);
        p++;
    }
}

status InitStack(stack *s,int n)
{
    s->stacksize = n;
    if(!(s->base = (BiTreeP*)malloc(sizeof(BiTreeP)))) return ERROR;
    s->top = s->base;
}

int push(stack *s,BiTree *ch)
{
    if(!(s->base + s->stacksize <= s->top))
    {
        BiTreeP *newbase;
        if(!(newbase = (BiTreeP*)realloc(s,(s->stacksize + STACKINCREMENT)*sizeof(BiTreeP))))
            return ERROR;
        else
        {
            s->stacksize += STACKINCREMENT;
            s->base = newbase;
            s->top = s->base + s->stacksize;
        }
    }
    *(s->top++) = ch;
    return OK;
}

int StackEmpty(stack *s)
{
    if(s->top = s->base) return 1;
    else return 0;
}

status main()
{
    BiTree *ps = NULL;
    stack *s = NULL;
    List *l = NULL;
    char * pl = NULL;
    int n;
    InitList(l);
    printf("How many data will be inputed ?\n");
    scanf("%d",&n);
    scandata(l,n);
    InitStack(s,n);
    if(!(ps = (BiTree*)malloc(sizeof(BiTree)))) return ERROR;
    push(s,ps);
    while(!StackEmpty(s))
    {
        while(*pl != '#')
        {
            if(!(ps->lchild = (BiTree*)malloc(sizeof(BiTree)))) return ERROR;
            ps->data = *pl;
            push(s,ps);
            ps =ps->lchild;
            pl++;
        }
        ps = ps->rchild;
        pl++;
    }
    return OK;
}

忘了说：这个程序是作用是实现二叉树的顺序建立
比如：
输入：
5//输入数据的总数
A
B
#
#
#
就可以按先序建立一个二叉树。
下面的主函数应该还会有很多错误，大家不用在这里纠缠过久，我纳闷的就是那个报错，辛苦大家啦！

五楼很到位，就是这的问题！我指针用得晕了。谢谢！