typedef struct node{
    elem_type data;
    struct node *lchild;
    struct node *rchild;
}tree_node,*tree_ptr;

int init_node(tree_ptr *pnode)
{
    pnode = (tree_ptr)malloc(sizeof(tree_node));
    if(pnode == NULL){
        printf("fail: malloc failed\n");
        exit(0);
    }
    pnode->lchild = pnode->rchild = NULL;
    pnode->data = 0;
    return 0;
}

上面pnode = (tree_ptr)malloc(sizeof(tree_node));
    pnode->lchild = pnode->rchild = NULL;
    pnode->data = 0;
这三条语句有错么？？望高手指点.....谢谢！

有木有错要看你的 elem_type 怎么定义了

int init_node(tree_ptr *pnode)
{
    pnode = (tree_ptr)malloc(sizeof(tree_node));//这句话好像不对吧
    if(pnode == NULL){
        printf("fail: malloc failed\n");
        exit(0);
    }
    pnode->lchild = pnode->rchild = NULL;
    pnode->data = 0;
    return 0;
}

应该是这样的 *pnode = (tree_ptr)malloc(sizeof(tree_node));  pnode是二级指针你要改变的是pnode所指向的东西的值

当然要加个取内容了吧

真细心