[说明]
任何一种程序都是为了解决问题而撰写的，解决问题时需要实现一些特定的运算法则。在策略(Strategy)模式下，可以更换实现算法的部分而不留痕迹，切换整个算法，简化改为采用其他方法来解决同样问题。
以下是一个“剪刀石头布”游戏。猜拳时的“策略”有2种方法：第一种是“猜赢后继续出同样的招式”(WinningStrategy)，第二种是“从上一次出的招式种，以概率分配方式求出下一个招式的几率”(ProbStrategy)。程序中定义了Hand类表示猜拳时的“手势”，类内部以0(石头)、1(剪刀)、2(布)来表示。Hand类的实例只会产生3个。
以下是C语言实现，省略了不相关属性及方法，方法实现体亦有所省略，能够正确编译通过。
[C代码]
typedef (1) (*funl)();
enum HandValueHANDVALUE_GUU=0, HANDVALUE_CHO=1, HANDVALUE_PAA=2;
//手势可取值，依次为“石头”、“剪刀”、“布”
//其大小顺序是循环相克的，即：石头赢剪刀，剪刀赢布，布赢石头
bool won;
struct Hand *WSprevHand;
struct Hand//手势
enum HandValue handvalue;
hand[3]=HANDVALUE_GUU, HANDVALUE_CHO, HANDVALUE_PAA;
int fight(struct Hand *h1, struct Hand *h2)
//比较h1和h2。h1代表的手势较大时返回1，h1较小时返回-1，相等时返回0
//

if(h1->handvalue == h2->handvalue)
return 0;
else if((h1->handvalue+1)% (2) == h2>handvalue)
return 1;
else
return -1;


struct Hand* getHand(int handvalue)
//依据手势代表的值取得手势，若handvalue不合法，返回NULL
switch(handvalue)
case 0:
return &hand[0];
break;
case 1:
return &hand[1];
bteak;
case 2;
return &hand[2];
break;

return (3) ;

struct Strategy//策略
funl nextHand;//下一个手势
;
struct Hand* WSnextHand()

if(!won)
PSprevHand = getHand(rand()%3);

return PSprevHand;

struct Player
char name[20];
(4) strategy;//策略
int wincount;
int losecount;
int gamecount;
;
void main()

Strategy WS;
WS.nextHand = WSnextHand;
WSpreVHand = NULL;
struct Player WSplayer;
(5)(WSplayer.name,"ww");
WSplayer.wincount = 0;
WSplayer.losecount = 0;
WSplayer.gamecount = 0;
WSplayer.strategy = &WS;

阅读理解

     Is there a nationwide shortage of nurses? It's hard to say. However, some characteristic symptoms

often indicate that there is indeed a shortage.

     One symptom is the vacancy rate, or the percentage of budgeted positions that are unfilled. New

England's hospitals currently report that an average of 7 to 12 percent of their registered nurse positions

are vacant, the highest level since the last shortage in the late 1980s. Vermont has a relatively low

vacancy rate, at 7.8 percent. But its vacancies were at 1.2 percent just five years ago.

     Another symptom is the increased use of stopgap measures to fill empty positions. For instance, many

nurses report an upswing in how frequently they are asked to stay past their shifts. According to Murphy, working in the St. Elizabeth's Hospital, "The shortage has definitely created a lot of opportunities of

overtime for our nurses, whether they want them or not." Similarly, a national survey of registered nurses

shows that in an average week, nurses in the U.S. work 2.4 more hours than they are scheduled to.

Much of this extra time is voluntary, as nurses earn overtime pay when they stay to fill in blanks in the

schedule.

     When they can't fill open positions by more traditional means, health care providers hire temporary

staff to tide them over. Travelling workers are the largest part of the temporary health care workforce,

hired for thirteen-week reduction at health care facilities facing short-term lack of workers. Temporary

workers, mainly nurses, cost hospitals $ 7.2 billion in 2000.

     "Any successful solution to the shortage depends on convincing more people to become nurses, and

that is not an easy goal to reach. To achieve it," says Buerhaus, "society needs to place more value on

nursing. Legislation (法规) can't do that - it should come from people." And if this continues, we might

have to learn to care for ourselves in the hospital.

1.The temporary staff hired by a hospital _______.

A. cost a large part of the hospital's budget

B. meet the need for nurses in the hospital for a short time

C. should work on a weekly basis and on a scheduled timetable  

D. ought to work passively for thirty continuous weeks

2. According to Buerhaus, what is a successful solution to the nurse shortage?  

A. To convince people of the benefits of being a nurse.

B. To ask the government for help to work out specific legislation.

C. To publicize the past achievements of nurses.

D. To make people aware of the importance of being a nurse.

3. What's the probable meaning of the underlined word "upswing" in Paragraph 3?

A. Symptom    

B. Decrease        

C. Increase      

D. Figure

4. What's the author's attitude towards nurse shortage?

A. Worried    

B. Indifferent        

C. Doubtful          

D. Optimistic