[说明]
基于管理的需要，每本正式出版的图书都有一个ISBN号。例如，某图书的ISBN号为“978-7-5606-2348-1”。
ISBN号由13位数字组成：前三位数字代表该出版物是图书(前缀号)，中间的9个数字分为三组，分别表示组号、出版者号和书名号，最后一个数字是校验码。其中，前缀号由国际EAN提供，已经采用的前缀号为978和979；组号用以区别出版者国家、地区或者语言区，其长度可为1～5位；出版者号为各出版者的代码，其长度与出版者的计划出书量直接相关；书名号代表该出版者该出版物的特定版次；校验码采用模10加权的算法计算得出。
校验码的计算方法如下：
第一步：前12位数字中的奇数位数字用l相乘，偶数位数字用3相乘(位编号从左到右依次为13到2)。
第二步：将各乘积相加，求出总和S。
第三步：将总和S除以10，得出余数R。
第四步：将10减去余数R后即为校验码V。若相减后的数值为10，则校验码为0。
例如，对于ISBN号“978-7-5606-2348-1”，其校验码为1，计算过程为：
S=9×1+7×3+8×1+7×3+5×1+6×3+0×1+6×3+2×1+3×3+4×1+8×3=139
R=139mod 10=9
V=10-9=1
函数check(char code[])用来检查保存在code中的一个ISBN号的校验码是否正确，
若正确则返回true，否则返回false。例如，ISBN号“978-7-5606-2348-1”在code中的
存储布局如表3-1所示(书号的各组成部分之间用“-”分隔)：
　　　　　　　　　　　　　　　 　　　　

表3-1 数组code的内容示例

在函数check(char code[])中，先将13位ISBN号放在整型数组元素tarr[0]～tarr[12]中(如表3-2所示，对应ISBN号的位13～位1)，由tarr[0]～tarr[11]计算出校验码放入变量V，再进行判断。

表3-2　数组tarr的内容示例

阅读理解。

     PITTSBURGH, Sept. 7-At 26, many people haven't even decided on a career. Luke Ravenstahl, cashing

in on his family's political tradition, is already the mayor of Pittsburgh, the youngest mayor of any major city

in the country. Although mayors elsewhere have been younger, Jeff Dunkel was 18 in 2001 when he was

elected mayor of Mount Carbon, small towns in New York, and elsewhere have also elected teenagers as

mayors. But, Tallahassee, is the only other city with a population over 100 000 that has had a mayor as young

as Mr. Ravenstahl. A supporter of Mr. Ravenstahl said concerns about Mr. Ravenstahl's age would dissipate

once the city saw his work ethic.

     But now comes the hard part. As he strives to be taken seriously and take charge of a city only recently

back from the edge of bankruptcy (破产), the baby-faced mayor said that even the smallest decisions felt

weighty, even what to wear in the Steelers game matters.

     And another pressing issue is to strengthen the city's economy. Pittsburgh has lost all its mills, nearly half

its population and much of its downtown commercial district in the last several decades. "But Pittsburgh has

50 000 college students, and our challenge is to figure out how to retain them and to increase downtown

development." He said.

     But one of the biggest uncertainties is how long he will remain in office. According to the city charter,

Mayor Ravenstahl's term will not expire until November 2009. Some city lawyers, however, have argued that

he must face the electorate next year. And residents in Pittsburgh are still keeping judgment on him Deli,

Jimmy Cvetic, a sandwich shop owner, said "I call him Cool Hand Luke. He'll be all right, but he's going to

need a cool hand to get through this." 

     Mayor Ravenstahl said he was still trying to deal with the challenge he faced.

1. About Luke Ravenstahl, which of the following statements is TRUE? [ ]

A. He is the youngest mayor in the U.S.A.

B. His family background has contributed to his successful political career.

C. His young age has won support from media and young voters.

D. He will be mayor of Pittsburgh at least until 2009.

2. The underlined word "dissipate" in the first paragraph probably means _____. [ ]

A. disappear

B. appear

C. spread

D. reduce

3. What can you infer from the article about Pittsburgh?[ ]

A. It is a small town in New York famous for steel mills.

B. It has always enjoyed prosperous economic success.

C. Many young college students there are the new hope of the district.

D. It is a major city in the U.S.A with a population slightly smaller than 100 000.

4. Where can you find this article? [ ]

A. A magazine.

B. A brochure about politicians.

C. A newspaper.

D. An advertisement about some mayor candidates.

5. What kind of challenges will not Luke Ravenstahl cope with? [ ]

A. distrust from his citizens.

B. pressure from other outstanding young mayors.

C. economical standstill of his city.

D. decreasing population in his city.