问题 填空题

栈的基本运算有三种:入栈、退栈和 【3】

答案

参考答案:读栈顶元素

解析: 栈实际上是一种特殊的线性表,其插入与删除运算都只在线性表的一端进行。即这种线性表的结构中,一端是封闭的,不允许插入和删除元素,另外一端是开口的,允许插入和删除元素。允许插入和删除元素的一端叫做栈顶,对栈顶的操作有三种方式,即入栈、退栈和读栈顶元素。

单项选择题
单项选择题

Who won the World Cup 1994 football game What happened at the United Nations How did the critics like the new play (1) an event takes place, newspapers are on the streets (2) the details. Wherever anything happens in the world, reporters are on the spot to (3) the news.

Newspapers have one basic (4) , to get the news as quickly as possible from its source, from those who make it to those who want to (5) it.

Radio, telegraph, television, and (6) inventions brought competition for newspaper. So did the development of magazines and other means of communication. (7) , this competition merely spurred the newspapers on. They quickly made use of the newer and faster means of communication to improve the (8) and thus the efficiency of their own operations. Today more newspapers are (9) and read than ever before. Competition also led newspapers to branch out into many other fields. Besides keeping readers (10) of the latest news, today’s newspapers (11) and influence readers about politics and other important and serious matters. Newspapers influence readers’ economic choices (12) advertising. Most newspapers depend on advertising for very (13) .

Newspapers are sold at a price that (14) even a small fraction of the cost of production. The main (15) of income for most newspapers is commercial advertising. The (16) in selling advertising depends on a newspaper’s value to advertisers. This (17) in terms of circulation. How many people read the newspaper

Circulation depends (18) on the work of the circulation department and on the services or entertainment (19) in a newspaper’s pages. But for the most part, circulation depends on a newspaper’s value to readers as a source of information (20) the community, city, county, state, nation, and world—and even outer space.

4()

A.reason

B.cause

C.problem

D.purpose