#include<stdio.h>
#include<stdlib.h>
#include<malloc.h>
/*树结构类型 */
typedef struct node
{
        int elem;
        struct node *lchild,*rchild;
}bitree_node;
/*栈结构类型*/
typedef struct stacknode
{
        bitree_node * tree_point;
        struct stacknode * next;
}stacknode;
typedef struct
{
        stacknode * top;
}stack;
stack * h;
/*栈的数据结构*/
void creat_stack(stack *h)
{
     h->top=NULL;
}
void push_stack(stack *h,bitree_node *e)
{
     stacknode * p;
     p=(stacknode *)malloc(sizeof(stacknode));
     p->tree_point=e;
     p->next=h->top;
     h->top=p;
}
void pop_stack(stack *h)
{
    stacknode *p;
    p=h->top;
    h->top=p->next;
    free(p);
}
bitree_node *top_stack(stack *h)
{
    return h->top->tree_point;
}
int stack_empty(stack *h)
{
    if(!h) return 0;
    else return 1;
}
/*树的数据结构*/
void creat_tree(bitree_node * bit)
{
    int rear=0,root,data;
    printf("请输入根结点\n");
    scanf("%d",&root);
    bit->elem=root;
    push(h,bit);
    bitree_node *p;
    while(1)
    {
            printf("请输入左孩子\n");
            scanf("%d",&data);
            if(data!=999)
            {
                   bit=(bitree_node *)malloc(sizeof(bitree_node));
                   bit->elem=data;
                   push_stack(h,bit);
                   bit=bit->lchild;
            }
            else
            {
          a:    p=top_stack(h);
                if(p->lchild!=NULL&&p->rchild!=NULL)
                {
                    pop_stack(h);
                    goto a;
                }
                p=p->rchild;
                printf("请输入右孩子\n");
                scanf("%d",&data);
                if(data==999)
                {
                    pop_stack(h);
                    goto a;
                }
                p->elem=data;
                push_stack(h,p);
                if(stack_empty(h)) break;
            }
    }
}
void main()
{
     h=(stack *)malloc(sizeof(stack));
     creat_stack(h);
     bitree_node * bit;
     bit=(bitree_node *)malloc(sizeof(bitree_node));
     creat_tree(bit);
}

不是 那个问题 你说的那个我后来加的 忘改了！是那top_stack函数在调试时出现错误