为您找到与union使用sql相关的共43个结果:
以下是短文写作中使用率最高、覆盖面最广的基本句式,每组句式的功能相同或相似,考生可根据自己的情况选择其中的1-2个,做到能够熟练正确地仿写或套用。下面是读文网小编整理的英文写作中使用率最高的基本句式,欢迎大家阅读!
1)It’s well known to us that ...
2)As is known to us,...
3)This is a topic that is being widely talked about.
4)From the graph(table,chart)listed above,it can be seen that ...
5)As a proverb says,“Where there is a will,there is a way.?
例如:
As is well known to us,it is important for the students to know the world outside campus.
The reason for this is obvious.Nowadays,the society is changing and developing rapidly,and the campus is no longer an “ivory tower?.As college students,we must get in touch with the world outside the campus.Only in this way can we adapt ourselves to the society quickly after we graduate.
再如:
Does it pay to be honest?This is a topic that is being widely talked about and different people have different opinions on it.
英文写作相关
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投简历是每个求职者都要做的一步,而简历的写作也是需要仔细研究的技能。在写作英文简历时,总是有那么几句“简历杀手”的出现让一些自以为没问题的求职者碰壁。快来看看你的简历中是否有类似的句子吧。
求职者们都从经历过的残酷现实中明白一个道理,那就是在求职中最难的就是怎样得到面试机会。一旦你得到了面试的机会,你就在这个过程中掌握了一些主动权,在这个阶段后,你就只需要做一些调查,然后发挥好就可以。
在这个过程中,简历担负的责任要比你本身担负的要重得多。它将你带入工作的大门。这就是求职者要避免在简历中使用以下5个“简历杀手”句子的原因了。看一看吧,你的简历中是否有这些句子呢?
不要想当然地认为你的资料非常突出,向我们表达出来吧。雇主都想知道你能够胜任此份工作,这就意味着你要为应聘的每一个职位定制一份简历。这些额外投入的时间是值得的,每个人都会有一份好工作的,很可能这份好工作就是你的。
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not only...but also 是英语中常见的一对连词, 相当中文的“不仅……而且”。Not only…but also是英语中较为常见的一个关联词组。由于它的用法比较复杂,本文拟对其用法及其使用中应注意的问题作一归纳。
1.”not only A but also B”结构中的A和B通常是同等成分。由于同一成分常常由同一词类的词来担任,所以A与B常常也是同一词性,这从本文第一部分的例句中即可看到。但是,也有A与B属于不同词性的情形。如:”He is not only very clever, but also a very hard worker, and he likes to do everything well.(他不但聪明,而且能下功夫。他喜欢把每一件事都做得很好。)其中A是形容词,B是名词,但两者均在句中作表语,因此仍是正确句子。然而,在“He not only plays the piano, but also the violin.”一句中,A是动词,B是名词,不是同一成分,因此语法学家认为此句有点欠妥,至少在书面语中就是如此。如改为“He plays not only the piano, but also the violin”就无懈可击了,再看下面二例:
The surprise grant not only enabled Dad to finish A&T, but to graduate first in his class.这笔意外的奖学金不仅使我父亲能读完农业和技术学院,而且毕业成绩名列榜首。
1.Not only spoke English very carefully, but very clearly as well.
2.有人认为,not only…but also不能用于否定句。汉语中用于否定句中的“不但…而且”在英语中要用as well as 表示。如“不但我不想看戏,而且他也不想看戏”可译作“He, as well as I, doesn’t want to see the play.”不过,这条规则也有例外,请看下面二例:
Not only did none of us know how the crime was to be committed, we didn’t even know what the crime was to be!
Not only don’t I know the population of Nepal, I don’t know where in god’s world it is!我不但不知道尼泊尔人口,而且连它究竟在哪里也不知道!
这两个例句有几个共同点:都是连接否定分句,都是倒装句,都没有用but also。下面一例出自一位美国作家之手,所不同的是,not only…but连接的是并列谓语,第一个动词是否定的,第二个动词则是肯定的:
Nonetheless, as he described Mary’s attitudes her accomplishments, he found himself wishing that she cared more about the police side of his life than she seemed to, that she might understand it as intimately, say, as the woman opposite him. But this motion seemed to him so disloyal to Mary that he not only did not articulate it, but at once tried to suppress it.
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下面是读文网小编整理的一些关于prefer的使用方法,欢迎大家阅读!
prefer最常见的意思是"宁可"、"宁愿(选择)"、"比较喜欢"、"更喜欢"等, 可以构成以下结构。
"Do you like French?""Yes, but I prefer English.""你喜欢法语吗?""喜欢,但是我更喜欢英语。"
"Which do you prefer, rice or bread?""Either will do.""你比较喜欢吃什么,米饭还是面包?""随便哪一个都行."
注:prefer是"比较喜欢,更喜欢"的意思,即like better,因此就不能再与better, more等比较级词语连用。
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摘要:研究者们已经开始试图找到更好在不同文体中使用表情的方法(emojis也许火过一阵子,但并没有其他传统校园表情前三那般流行:笑脸,皱眉和眨眼。)他们的研究告诉我们如何在网上约会抑或回复专业邮件时充分利用表情符号。
The battle is over and the emoticons have won. Whatever you think of the symbols, they’re absolutely everywhere, including in work emails. But the etiquette over emoticon usage is still fuzzy, and it’s an understandable source of tension, especially considering that people may be judging us based on our smiley deployment.
Luckily, researchers are starting to better understand how people perceive emoticons in various contexts (emojis may be having a moment, but they’re not as universal as the top three old-school emoticons: the smiley, the frowny, and the winky). Their work can provide some helpful pointers on how to use your emoticons to maximum effect, whether dating online or responding to a professional email.
斗争结束情感获胜。无论你怎么看待表情符号,它们真真无处不在,哪怕是工作的邮件。但如何使用这些表达感情的符号并没有明确的规则,也可看成是我们紧张情绪的舒缓,尤其是意识到别人可能会根据我们发出的表情符号对我们自身做出判断。
好在,研究者们已经开始试图找到更好在不同文体中使用表情的方法(emojis也许火过一阵子,但并没有其他传统校园表情前三那般流行:笑脸,皱眉和眨眼。)他们的研究告诉我们如何在网上约会抑或回复专业邮件时充分利用表情符号。
Here are five ways to be a smarter emoticon user:
怎样科学地使用聊天表情
下面五招教你做一个聪明的表情使用者:
1. If you want to be popular, limit how many frownies you use.
Language and culture have been shown to color how emoticons are used and interpreted, as was recently demonstrated in a 2013 study of tweets from around the world. In Japan and South Korea, for instance, emoticons are more likely to be horizontally oriented (think @_@) ), as opposed to the standard American :), which is vertically oriented unless your mail program or phone turns it into a graphic for you.
在对2013年全球推特的研究中发现语言和文化会影响表情的使用和含义。比如日本韩国,表情更加倾向于横向(思考@_@),然而标准的美式表情:),是纵向的。除非你的邮件系统或电话自动为你修改。
In the Philippines and Indonesia, however, where English is spoken along with local languages, emoticons are just as likely to be vertically oriented. And in languages read from right to left, such as Arabic and Hebrew, smileys are reversed, like (: . South Americans apparently “are known to explore various types of eyebrows in their emoticons,” according to the study authors. So if you’re sending emoticons to foreign friends, a bit of research can help bridge the communication gap.
然而在菲律宾和印度尼西亚,英语和当地语言混杂使用,表情符号也似乎偏纵向。而对于从右往左阅读的语言,比如阿拉伯语和希伯来语,笑脸也会反过来(:。研究发现南美显然”被认为在表达情绪中更热衷于使用眉毛 “。所以如果你给国外的朋友发送表情,一点小调查能帮助你缩短交流代沟哦。
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随着津巴布韦经济发展乏力,政府日益求助于中国提振疲弱的津巴布韦经济。希望增加人民币的使用加强两国之间的双边贸易。下面读文网小编为大家带来金融财经双语阅读《津巴布韦鼓励使用人民币》,希望大家喜欢!
Zimbabwe will encourage the use of China’s currency to pay for anything from groceries to tourist curios as president Robert Mugabe’s government turns ever more closely to Beijing to bolster its ailing economy. 津巴布韦将鼓励使用人民币来支付从食品到旅游纪念品的各种商品。罗伯特·穆加贝(Robert Mugabe)总统的政府日益求助于中国提振疲弱的津巴布韦经济。
After announcing that China had agreed to cancel $40m of debt due this year, Patrick Chinamasa, Zimbabwe’s finance minister, said he hoped that boosting the use of the renminbi would bolster bilateral trade between the countries. 在宣布中国已同意取消今年到期的4000万美元债务后,津巴布韦财政部长帕特里克·奇纳马萨(Patrick Chinamasa)表示,他希望增加人民币的使用将加强两国之间的双边贸易。
Mr Mugabe, Zimbabwe’s veteran president, has increasingly looked to Beijing to help prop up the country’s economy in recent years. In contrast, western nations have largely treated Mr Mugabe as a pariah since the 2000s because of his regime’s forced seizure of white-owned farms and human rights abuses committed against political opponents. 长期掌权的津巴布韦总统穆加贝近年越来越寄望于北京方面帮助支撑该国经济。与此形成反差的是,西方国家自本世纪初以来基本上对穆加贝抱有敌意,因为他的政权强制没收白人拥有的农场,并侵犯政治反对派的人权。
The renminbi was added to a list of currencies that are legal tender in Zimbabwe early last year, but has been little used. More than 85 per cent of transactions in the nation are estimated to be undertaken in US dollars while the rand, the currency of neighbouring South Africa, is also used widely. 人民币在去年初加入津巴布韦法定货币的名单,但迄今使用不多。该国估计有85%以上的交易用美元进行,而邻国南非的货币兰特也被广泛使用。
Harare ditched its own currency, the Zimbabwe dollar, in 2009 following a period of hyperinflation that soared to record levels as the central bank issued Z$100,000bn notes that lost value almost as soon as they were printed. Analysts said the decision to attempt to increase the use of the renminbi was largely a political gesture. 哈拉雷方面在2009年放弃了本币津巴布韦元。在那之前的恶性通胀时期,随着通胀飙升至创纪录水平,就连央行发行的100万亿津巴布韦元面值的纸币也很快失去价值。分析师们表示,试图增加使用人民币的决定在很大程度上是一种政治姿态。
Mr Chinamasa gave the example of Chinese tourists being able to use renminbi in the country. 奇纳马萨列举了中国游客能够在该国使用人民币的例子。
“We can make that facility available,” Mr Chinamasa told Zimbabwe’s Sunday Mail, a state-owned newspaper. “What we and the People’s Bank of China then need to do after collecting this currency is have a system of clearance so that we are able to use what has been paid for in the renminbi for our services in Zimbabwe.” “我们可以提供这样的设施,”奇纳马萨对津巴布韦国有报纸《星期日邮报》(Sunday Mail)表示。“在收集这些货币后,我们和中国人民银行(PBoC)需要做的是拥有一个清算体系,使我们能够接受用人民币支付津巴布韦的服务。”
Last month Mr Mugabe, 91, paid tribute to Beijing during a state visit to Zimbabwe by Xi Jinping, China’s president, saying “we greatly appreciate the understanding and flexibility shown by China.” 上月,在中国国家主席对津巴布韦进行国事访问期间,91岁的穆加贝赞扬北京,称:“我们十分赞赏中国展示的理解和灵活性。”
During that two-day visit, government officials said deals had been agreed worth $4bn covering a wide range of sectors, including financial support for the construction of a new parliament building and the expansion of power stations. But there were concerns that Chinese financing would increase Zimbabwe’s heavy debt burden, while many of the projects had already been under discussion for years. 政府官员们表示,在那次为期两天的访问期间,双方达成了价值40亿美元的交易,涵盖众多领域,包括资助建设一栋新的议会大厦,以及扩建电站。但有人表示担心,中国的资金将增加津巴布韦沉重的债务负担,而且其中许多项目已经被讨论了多年。
Zimbabwean officials often claim that China is now Zimbabwe’s second largest trading partner. But the latest foreign trade figures show that China’s share of trade falls behind that of South Africa, which accounts for about half of Zimbabwe’s imports and exports, and Singapore and Mozambique. 津巴布韦官员经常声称,中国现在是津巴布韦的第二大贸易伙伴。但最新外贸数据显示,中国的贸易份额落后于南非(占津巴布韦进出口的大约一半),以及新加坡和莫桑比克。
Mr Kipson Gundani, chief economist of Buy Zimbabwe, said he did not think that the Chinese currency was not about to be widely used, adding that the effect of Mr Chinamasa’s announcement would be “close to zero.” “购买津巴布韦”(Buy Zimbabwe)首席经济学家Kipson Gundani表示,他不认为人民币即将获得广泛使用。他补充称,奇纳马萨所宣布决定的效果将“接近于零”。
John Robertson, an independent economist, added: “There is a shortage of money in the economy and introduction of the Chinese [renminbi] won’t make much difference.” 独立经济学家约翰·罗伯逊(John Robertson)表示:“经济中缺乏资金,引入人民币不会带来多大差别。”
Harare’s attempts to enhance the use of the renminbi comes at a time of huge economic challenges in Zimbabwe. 哈拉雷方面试图增加人民币使用之际,津巴布韦面临着巨大的经济挑战。
Since an initial bounce in growth after Harare allowed the US dollar to be used as the main currency, economic growth has slumped amid risks that it could fall back into recession. The government and the International Monetary Fund forecast growth of 1.5 per cent this year. But with drought, severe electricity shortages and a collapse in commodity prices, as well as political uncertainty, other economists think such a prediction overly optimistic. 在哈拉雷方面允许美元被用作主要货币后,津巴布韦经济最初有所反弹,但自那以来已经下滑,面临重新陷入衰退的风险。政府和国际货币基金组织(IMF)预测今年经济增长1.5%。但是,面对干旱、严重电力短缺、大宗商品价格崩盘,以及政治不确定性,其他经济学家认为这样的预测过于乐观。
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天使本义指上帝的使者,来自天上的使者,代表圣洁、良善,正直。那么你想知道天使用英语怎么说吗?下面读文网小编为大家带来天使的英语说法,欢迎大家参考学习。
炽天使 Seraphim
银河天使 Galaxy Angel
守护天使 Guardian Angel
大天使 Archangels
天使游戏 The Angel's Game
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小编为大家整理了c语言 union的用法。希望对你有帮助哦!
下面举几个例子:
(1). 判断系统用的是big endian 还是 little endian(其定义大家可以到网上查相关资料,此略)
#define TRUE 1
#define FALSE 0
#define BOOL int
BOOL isBigEndian()
{
int i = 1; /* i = 0x00000001*/
char c = *(char *)&i; /* 注意不能写成 char c = (char)i; */
return (int )c != i;
}
如果是little endian字节序的话,那个i = 1;的内存从小到大依次放的是:0x01 0x00 0x00 0x00,如是,按照i的起始地址变成按照char *方式(1字节)存取,即得c = 0x01;
反之亦然
也许看起来不是很清晰,下面来看一下这个:
BOOL isBigEndian()
{
union
{
int i;
char c;
}test;
test.c = 2;
return test.i != 2;
}
这里用的是union来控制这个共享布局,有个知识点就是union里面的成员c和i都是从低地址开始对齐的。同样可以得到如此结果,而且不用转换,清晰一些。
什么,不觉得清晰??那再看下面的例子:
(2). 将little endian下的long long类型的值换成 big endian类型的值。已经知道系统提供了下面的api:long htonl(long lg);作用是把所有的字节序换成大端字节序。因此得出下面做法:
long long htonLL(long long lg)
{
union
{
struct
{
long low;
long high;
}val_1;
long long val_2;
}val_arg, val_ret;
if ( isBigEndian() )
return lg;
val_arg.val_2 = lg;
val_ret.val_1.low = htonl( val_arg.val_1.high );
val_ret.val_1.high = htonl( val_arg.val_1.low );
return val_ret.val_2;
}
只要把内存结构的草图画出来就比较容易明白了。
(3).为了理解c++类的布局,再看下面一个例子。有如下类:
class Test
{
public :
float getFVal(){ return f;}
private :
int i;
char c;
float f;
};
Test t;
不能在类Test中增加代码,给对象中的f赋值7.0f.
class Test_Cpy
{
public :
float getVal(){ return f;}
float setVal(float f){ this ->f = f;}
private :
int i;
char c;
float f;
};
....
int main()
{
Test t;
union
{
Test t1,
Test_Cpy t2;
}test;
test.t2.setVal(7.0f);
t = test.t1;
assert( t.getVal() == 7.0f );
return 0;
}
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炽天使是在《旧约圣经》中提到的六翼天使;亦出现于不同的中东作品,被视为天神。犹太教认为此类天使拥有人类的外表,而基督教神学则把炽天使分为天阶中最高级“神圣的阶级”的最高等级。那么你知道炽天使用英语怎么说吗?下面来学习一下吧。
雄伟权杖-圣水喷杖-炽天使法杖
Grand Scepter-Holy Water Sprinkler-Seraph Rod
根据以诺书所说,每一位炽天使都有六个翅膀(六翼)。
According to Enoch, each seraphim has six wings.
炽天使拥有一把宝剑能使在战场上牺牲的英灵复生。
The Seraph has a blade that can bring a valiant soul back to life on the battlefield.
炽天使战士们以充满了正义之气和审判力量的光明之剑打击敌人。
Seraphim warriors strike at the enemies of Light with swords imbued with righteous wrath and justice.
炽天使是第一个也是唯一的专为女性提供的脂肪燃烧器。
Lipo 6 Hers is the first and only fat burner specifically designed for women that offers speed and duration.
高等精灵-炽天使的一个优秀种族,利用控制能量的优势慢慢成为了这个世界的精英。
The High Elves, the preferred race of the Seraphim, took advantage of the creative energy instilled within the very essence of the world.
从不列颠空战到珍珠港,炽天使二战是从育碧动作游戏,你从一个菜鸟成长为一个身经百战的王牌。
From the Battle of Britain to Pearl Harbor, Blazing Angels is a WWII action game from Ubisoft where you grow from a rookie to a battle-scarred ace.
当炽天使出现在阵营中时,神圣帝国的战士们会充满勇气,无畏死亡,因为死亡对他们来说并非永恒。
Soldiers of the Holy Empire fight with greater courage and less fear when there is a Seraph amongst their ranks, for death is not necessarily permanent.
仰望天空,仿佛看到炽天使挥舞着双翼,袭来阵阵的暖风,带着荆棘花的香味,然后告诉我,我已经找到天堂。
Look at the sky, as if to see Blazing Angels waving wings, hit bursts of warm air, the smell of flowers with thorns, and then told me that I have found paradise.
一旦炽天使出现在阵营中时,神圣帝国的战士们会充满勇气,不惧牺牲,因为死亡对他们来说并非永恒。
Soldiers of the Holy Empire fight with greater courage and less fear when there is a Seraph amongst their ranks, for death is not necessarily permanent.
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书签与收藏夹就相当于电脑把把你需要的网页的网址储存下来,下回你需要的时候点一下那个储存的书签就可以打开您之前的那个网站。接下来小编为大家整理了如何使用书签与收藏夹。希望对你有帮助哦!
Soon you will discover that you've got dozens of bookmarks. It's now time to organize them into folders
If you use Internet Explorer 5.0,click on the Favorites button on the toolbar to open the Favorites window. Now select Organize Favorites. Click on the folder icon to create a new folder, then name it. We suggest organizing your bookmarks in folders by subjects*, such as Food, Travel, News, Sports, etc. Now click on each Favorite once, hold down your left mouse key and drag the appropriate Favorite into the subject folder.
If you use Navigator 4.0 or a later release,lick on the Bookmarks icon to view all your bookmarks. Under the File menu,select New Folder. In the Name box,type in a name for the folder, then click on OK. Now return to your list of bookmarks click once on one to highlight it,then drag it into the appropriate subject-related folder. Repeat the process for the other topics and bookmarks.
Sometimes the names of the bookmarks aren't descriptive, so you may want to alter them. With Navigator,select the bookmark you want to change by clicking on it once. Go to the Edit menu and choose Bookmark Properties. Now type in the new name and click OK.
With Explorer,open the Favorites window,then click on Organize Favorites. After the dialog box opens,click on the favorites you want to change. Next,click the Rename button. Now you can type a new name.
注释:
folder:文件夹
Organize Favorites:整理收藏夹
subject:主题
release:版本
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雅思听力具有内容多样性和语言复杂性等特点,在听力理解的过程中,图式会依据题目信息的刺激被激活,对信息进行推理、整合和构建,因此在题目信息的刺激下,心理图式会相继展开激活、推理、整合和重新构建等功能。下面小编就跟大家分享下雅思听力资料使用方法。
在保证语言正确的前提下,复述可有越来越大的灵活性,如改变句子结构,删去一些不大有用或过难的东西,长段可以缩短,甚至仅复述大意或作内容概要。不管是跟读还是复述原文,都需要花费大量的时间,而且效果也不是马上就能体现出来,但是只要坚持一段时间,每天各做30分钟左右,你就会发现自己的语言水平有很大的提高。跟读的材料可以选择新概念,根据自己的水平选择从二还是从三开始。在跟读的时候要不断比较自己和录音原文的区别,一般要读准一句话需要花两到三遍左右,才能准确模仿语音。 要提高听力能力,首先是要解决词汇的问题,要熟悉听力教材中和日常口语中所出现的句型和表达法,把增强语感放到重要位置上来加以强调。没有足够词汇量,听力不可能提高的。没有一定量的句型,在和英美人交流的时候就会在表达上形成差距,造成交流障碍。所以词汇是第一步,同时要扩大对句型的掌握,背词汇的同时要大量记忆常用的句型结构, 在听力教材中出现的生词要背,词组和句型更是要熟练掌握。
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使用,使人员、器物、资金等为某种目的的服务。那么你知道使用用英语怎么说吗?下面来学习一下吧。
使用寿命 service life ; Life Time ; useful life ; Lifespan
使用者 users ; The User ; end user ; power user
使用方便 easy to use ; convenient to use ; Easy to Use Everyday ; Easy to adjust
使用期限 life time ; service life ; Age ; life span
使用费 access fee ; user charges ; Toll ; User Fees
使用DHCP Using DHCP
使用环境 Environment ; Operational environment ; Usage environment ; Working Environment
在使用 in use ; use ; Subject to use ; be used in
使用案例 use case ; Business Use Case ; application cases ; black-box use case
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c语言中union的用法的用法你知道吗?下面小编就跟你们详细介绍下c语言中union的用法的用法,希望对你们有用。
01.struct Matrix
02.{
03. union
04. {
05. struct
06. {
07. float _f11, _f12, _f13, _f21, _f22, _f23, _f31, _f32, _f33;
08. };
09. float f[3][3];
10. }_matrix;
11.};
13.struct Matrix m;
这两个东西共同使用相同的空间,所以没有空间浪费,在需要整体用矩阵的时候可以用
m._matrix.f (比如说传参,或者是整体赋值等);需要用其中的几个元素的时候可以用m._matrix._f11那样可以避免用m.f[0][0](这样不大直观,而且容易出错)。
2. 用在强制类型转换上(比强制类型转换更加容易看懂)
下面举几个例子:
(1). 判断系统用的是big endian 还是 little endian(其定义大家可以到网上查相关资料,此略)
01.#define TRUE 1
02.#define FALSE 0
03.#define BOOL int
06.BOOL isBigEndian()
07.{
08. int i = 1; /* i = 0x00000001*/
09. char c = *(char *)&i; /* 注意不能写成 char c = (char)i; */
10. return (int )c != i;
11.}
如果是little endian字节序的话,那个i = 1;的内存从小到大依次放的是:0x01 0x00 0x00 0x00,如是,按照i的起始地址变成按照char *方式(1字节)存取,即得c = 0x01;
反之亦然
也许看起来不是很清晰,下面来看一下这个:
01.BOOL isBigEndian()
02.{
03. union
04. {
05. int i;
06. char c;
07. }test;
09. test.c = 2;
11. return test.i != 2;
12.}
这里用的是union来控制这个共享布局,有个知识点就是union里面的成员c和i都是从低地址开始对齐的。同样可以得到如此结果,而且不用转换,清晰一些。
什么,不觉得清晰??那再看下面的例子:
(2). 将little endian下的long long类型的值换成 big endian类型的值。已经知道系统提供了下面的api:long htonl(long lg);作用是把所有的字节序换成大端字节序。因此得出下面做法:
01.long long htonLL(long long lg)
02.{
03. union
04. {
05. struct
06. {
07. long low;
08. long high;
09. }val_1;
10. long long val_2;
11. }val_arg, val_ret;
14. if ( isBigEndian() )
15. return lg;
16. val_arg.val_2 = lg;
19. val_ret.val_1.low = htonl( val_arg.val_1.high );
20. val_ret.val_1.high = htonl( val_arg.val_1.low );
22. return val_ret.val_2;
23.}
只要把内存结构的草图画出来就比较容易明白了。
(3).为了理解c++类的布局,再看下面一个例子。有如下类:
01.class Test
02.{
03.public :
04. float getFVal(){ return f;}
05.private :
06. int i;
07. char c;
08. float f;
09.};
10.Test t;
不能在类Test中增加代码,给对象中的f赋值7.0f.
01.class Test_Cpy
02.{
03. public :
04. float getVal(){ return f;}
05. float setVal(float f){ this ->f = f;}
06.private :
07. int i;
08. char c;
09. float f;
10.};
12.....
14.int main()
15.{
16. Test t;
17. union
18. {
19. Test t1,
20. Test_Cpy t2;
21. }test;
23. test.t2.setVal(7.0f);
24. t = test.t1;
25. assert( t.getVal() == 7.0f );
27. return 0;
28.}
说明:因为在增加类的成员函数时候,那个类的对象的布局基本不变。因此可以写一个与Test类一样结构的类Test_Cpy,而多了一个成员函数setVal,再用uinon结构对齐,就可以给私有变量赋值了。(这种方法在有虚机类和虚函数机制时可能失灵,故不可移植)至于详细的讨论,网上有,这个例子在实际中没有用途,只是用来考察这个内存布局的使用而已.
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数据库中union的用法的用法你知道吗?下面小编就跟你们详细介绍下数据库中union的用法的用法,希望对你们有用。
UNION 指令的目的是将两个 SQL 语句的结果合并起来。从这个角度来看, UNION 跟 JOIN 有些许类似,因为这两个指令都可以由多个表格中撷取资料。 UNION 的一个限制是两个 SQL 语句所产生的栏位需要是同样的资料种类。另外,当我们用 UNION这个指令时,我们只会看到不同的资料值 (类似 SELECT DISTINCT)。 union只是将两个结果联结起来一起显示,并不是联结两个表………… UNION 的语法如下: [SQL 语句 1]
UNION
[SQL 语句 2] 假设我们有以下的两个表格,
Store_Information 表格
store_name Sales Date
Los Angeles $1500 Jan-05-1999
San Diego $250 Jan-07-1999
Los Angeles $300 Jan-08-1999
Boston $700 Jan-08-1999
Internet Sales 表格
Date Sales
Jan-07-1999 $250
Jan-10-1999 $535
Jan-11-1999 $320
Jan-12-1999 $750
而我们要找出来所有有营业额 (sales) 的日子。要达到这个目的,我们用以下的 SQL 语句: SELECT Date FROM Store_Information
UNION
SELECT Date FROM Internet_Sales 结果:
Date
Jan-05-1999
Jan-07-1999
Jan-08-1999
Jan-10-1999
Jan-11-1999
Jan-12-1999
有一点值得注意的是,如果我们在任何一个 SQL 语句 (或是两句都一起) 用 "SELECT DISTINCT Date" 的话,那我们会得到完全一样的结果。
SQL Union All
UNION ALL 这个指令的目的也是要将两个 SQL 语句的结果合并在一起。 UNION ALL 和 UNION 不同之处在于 UNION ALL 会将每一笔符合条件的资料都列出来,无论资料值有无重复。 UNION ALL 的语法如下: [SQL 语句 1]
UNION ALL
[SQL 语句 2] 我们用和上一页同样的例子来显示出 UNION ALL 和 UNION 的不同。同样假设我们有以下两个表格,
Store_Information 表格
store_name Sales Date
Los Angeles $1500 Jan-05-1999
San Diego $250 Jan-07-1999
Los Angeles $300 Jan-08-1999
Boston $700 Jan-08-1999
Internet Sales 表格
Date Sales
Jan-07-1999 $250
Jan-10-1999 $535
Jan-11-1999 $320
Jan-12-1999 $750
而我们要找出有店面营业额以及网络营业额的日子。要达到这个目的,我们用以下的 SQL 语句: SELECT Date FROM Store_Information
UNION ALL
SELECT Date FROM Internet_Sales 结果:
Date
Jan-05-1999
Jan-07-1999
Jan-08-1999
Jan-08-1999
Jan-07-1999
Jan-10-1999
Jan-11-1999
Jan-12-1999
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在mysql数据库中 rank的用法的用法你知道吗?下面小编就跟你们详细介绍下在mysql数据库中 rank的用法的用法,希望对你们有用。
Write a SQL query to rank scores. If there is a tie between two scores, both should have the same ranking. Note that after a tie, the next ranking number should be the next consecutive integer value. In other words, there should be no "holes" between ranks.
?
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+----+-------+
| Id | Score |
+----+-------+
| 1 | 3.50 |
| 2 | 3.65 |
| 3 | 4.00 |
| 4 | 3.85 |
| 5 | 4.00 |
| 6 | 3.65 |
+----+-------+
For example, given the above Scores table, your query should generate the following report (order by highest score):
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+-------+------+
| Score | Rank |
+-------+------+
| 4.00 | 1 |
| 4.00 | 1 |
| 3.85 | 2 |
| 3.65 | 3 |
| 3.65 | 3 |
| 3.50 | 4 |
+-------+------+
题目解答:
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# Write your MySQL query statement below
SELECT Scores.Score, COUNT(Ranking.Score) AS RANK
FROM Scores
, (
SELECT DISTINCT Score
FROM Scores
) Ranking
WHERE Scores.Score <= Ranking.Score
GROUP BY Scores.Id, Scores.Score
ORDER BY Scores.Score DESC;
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使用寿命是指企业使用固定资产的预计期间,或者该固定资产所能生产产品或提供劳务的数量。那么你知道使用寿命用英语怎么说吗?接下来跟着读文网小编来学习一下吧。
service life
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促使的意思是推动某物或使某事达到一定目的,如:这些动机促使他担负起吃力而又不讨好的工作。你知道促使用英语怎么说吗?下面读文网小编为大家带来促使的英语说法,欢迎大家学习。
spur
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