小编Hal*_*mil的帖子

我有一个关于解析树的问题:

我有一个字符串(math expresion estring),例如:(a+b)*c-(d-e)*f/g.我必须在树中解析该表达式:

class Exp{};
class Term: public Exp{
    int n_;
}

class Node: Public Exp{
    Exp* loperator_;
    Exp* roperator_;
    char operation; // +, -, *, /
}

我可以用什么算法来构建一个代表上面表达式字符串的树？

开始了:

mysql> LOCK TABLES radcheck WRITE;
Query OK, 0 rows affected (0.00 sec)

mysql> SELECT * FROM radcheck WHERE id NOT IN (
    ->     SELECT id FROM (
    ->         SELECT id FROM radcheck  WHERE attribute = 'Password' GROUP BY UserName HAVING COUNT(*) > 1
    ->      ) AS c
    -> );
ERROR 1100 (HY000): Table 'radcheck' was not locked with LOCK TABLES

WTF？

编辑

SET AUTOCOMMIT = 0
    -> ;
Query OK, 0 rows affected (0.00 sec)

mysql> LOCK TABLES radcheck …

我有以下python脚本(tes.py):

#!/usr/bin/env python
# -*- coding: utf-8 -*-

import MySQLdb

query = "INSERT INTO test(test) VALUES ('ñ')"
print query + "\n"

conn = MySQLdb.connect (host = "localhost", user = "ibrick", passwd = "x", db = "ibrick", charset="utf8")
conn.names="utf8"
cursor = conn.cursor()
cursor.execute (query);
cursor.close ()
conn.commit ()

文件编码utf-8:

 $ file -i tes.py 
tes.py: text/x-java charset=utf-8

系统编码UTF:

#locale
LANG=es_AR.UTF-8
LC_CTYPE="es_AR.UTF-8"
LC_NUMERIC="es_AR.UTF-8"
LC_TIME="es_AR.UTF-8"
LC_COLLATE="es_AR.UTF-8"
LC_MONETARY="es_AR.UTF-8"
LC_MESSAGES="es_AR.UTF-8"
LC_PAPER="es_AR.UTF-8"
LC_NAME="es_AR.UTF-8"
LC_ADDRESS="es_AR.UTF-8"
LC_TELEPHONE="es_AR.UTF-8"
LC_MEASUREMENT="es_AR.UTF-8"
LC_IDENTIFICATION="es_AR.UTF-8"
LC_ALL=
echo "ñññ" > /tmp/test.txt

file /tmp/test.txt 
/tmp/test.txt: UTF-8 Unicode …