Unit3-Computer Language and Programming

1、劉曉璐 講師Section A Programming Language課文課文A 編程語言編程語言Unit 3 Computer Language and Programming第三單元第三單元 計算機語言與編程計算機語言與編程Unit 3 Computer Language and Programming2I.Introduction Programming languages, in computer science, are the artificial languages used to write a sequence of instructions (a computer pro

2、gram) that can be run by a computer. 在計算機科學(xué)中，在計算機科學(xué)中，編程語言編程語言是用于是用于編寫可由計算機運行的編寫可由計算機運行的一系列指令一系列指令（計（計算機程序）的算機程序）的人工語言人工語言。定語從句定語從句過去分詞做定語過去分詞做定語Unit 3 Computer Language and Programming3Similar to natural languages, such as English, programming languages have a vocabulary, grammar, and syntax.vocabul

3、aryvkbjlrn. 詞匯grammargrm(r) n.語法syntaxsntks n.句法與英語等自然語言相類似，編程語言有詞匯、語法和句法。Unit 3 Computer Language and Programming4However, natural languages are not suited for programming computers because they are ambiguous, meaning that their vocabulary and grammatical structure may be interpreted in multiple wa

4、ys.ambiguousmbgjusadj.含糊的，不明確的；引起歧義的interpretnt:prt vt.解釋；理解；詮釋然而，自然語言不適合為計算機編程，因為它們會引起歧義，也就是說它們的詞匯和語法結(jié)構(gòu)可能被用多種方式進行解釋。原因狀語從句原因狀語從句賓語從句，賓語從句，meaning的賓語的賓語Unit 3 Computer Language and Programming5The languages used to program computers must have simple logical structures, and the rules for their gramma

5、r, spelling and punctuation must be precise.punctuation,pktuenn.標點符號的使用；標點符號；preciseprsasadj.清晰的；精確的；正規(guī)的用于計算機編程的語言必須有簡單的邏輯結(jié)構(gòu)，它們的語法、拼寫和標點符號規(guī)則必須精確。過去分詞做定語過去分詞做定語Unit 3 Computer Language and Programming6 Programming languages vary greatly in their sophistication and in their degree of versatility. Some

6、 programming languages are written to address a particular kind of computing problem or for use on a particular model of computer system.varyvervi.變化,不同; vt.使不同,使多樣化sophistications,fstkenn. 老練,精明;復(fù)雜versatility,v:stltn.多才多藝；多用途addressdresvt.在寫姓名地址；講演；處理；稱呼 編程語言在復(fù)雜性和通用程度上差異很大。一些編程語言是為了處理特定類型的計算問題或為了用于

7、特定型號的計算機系統(tǒng)而編寫的。Unit 3 Computer Language and Programming7For instance, programming languages such as FORTRAN and COBOL were written to solve certain general types of programming problems FORTRAN for scientific applications, and COBOL for business applications.FORTRANf:trn: FORTRAN語言，公式翻譯程序語言 (Formula

8、 Translation 的縮寫)COBOLkbl: COBOL語言，面向商業(yè)的通用語言(Common Business-Oriented Language 的縮寫)例如，F(xiàn)ORTRAN和COBOL等編程語言是為解決某些普遍的編程問題類型而編寫的FORTRAN是為了科學(xué)領(lǐng)域的應(yīng)用，而COBOL是為了商業(yè)領(lǐng)域的應(yīng)用。Unit 3 Computer Language and Programming8Although these languages were designed to address specific categories of computer problems, they are

9、highly portable, meaning that they may be used to program many types of computers. portablep:tbladj.手提的；便攜的；輕便的盡管這些語言旨在處理特定類型的計算機問題，但它們具有很高的可移植性，也就是說它們可以用來為多種類型的計算機編程。賓語從句，賓語從句，meaning的賓語的賓語Unit 3 Computer Language and Programming9Other languages, such as machine languages, are designed to be used b

10、y one specific model of computer system, or even by one specific computer in certain research applications. 其他的語言，如機器語言，是為一種特定型號的計算機系統(tǒng)，甚至是一臺特定的計算機，在某些研究領(lǐng)域使用而編寫的。Unit 3 Computer Language and Programming10The most commonly used programming languages are highly portable and can be used to effectively s

11、olve diverse types of computing problems. Languages like C, PASCAL, and BASIC fall into this category.diversedav:sadj.不同的，多種多樣的，變化多的最常用的編程語言具有很高的可移植性，可以用于有效地解決不同類型的計算問題。像C、PASCAL和BASIC這樣的語言就屬于這一范疇。Unit 3 Computer Language and Programming11Fill the blanksA programming language is any language that ca

12、n be used to write a sequence of that can ultimately be processed and executed by a computer.artificial instructionsTranslate自然語言natural languagesUnit 3 Computer Language and Programming12II.Language Types Programming languages can be classified as either low-level languages or high-level languages.

13、 Low-level programming languages, or machine languages, are the most basic type of programming languages and can be understood directly by a computer. Machine languages differ depending on the manufacturer and model of computer. 編程語言可分為低級語言和高級語言。低級編程語言或機器語言，是編程語言中最基礎(chǔ)的類型，可以被計算機直接理解。機器語言視計算機制造商與型號不同而有

14、所區(qū)別。Unit 3 Computer Language and Programming13High-level languages are programming languages that must first be translated into a machine language before they can be understood and processed by a computer. Examples of high-level languages are C, C+, PASCAL, and FORTRAN. 高級語言是必須首先翻譯成機器語言計算機才能理解和處理的編程

15、語言。C、C+、PASCAL和FORTRAN都是高級語言的例子。定語從句定語從句狀語從句狀語從句Unit 3 Computer Language and Programming14Assembly languages are intermediate languages that are very close to machine languages and do not have the level of linguistic sophistication exhibited by other high-level languages, but must still be translate

16、d into machine language.assemblysembln.裝配;集會;議會;代表大會intermediate,ntmi:ditadj.中間的，中級的linguisticlgwstkadj.語言的；語言學(xué)的sophistications,fstkenn.復(fù)雜exhibitzbtvt.陳列，展覽；呈現(xiàn)；證明；定語從句定語從句過去分詞短語過去分詞短語匯編語言是中級語言，非常接近于機器語言，沒有其他高級語言所表現(xiàn)出的語言復(fù)雜程度，但仍然得翻譯成機器語言。Unit 3 Computer Language and Programming15Fill the blanksWe can c

17、lassify programming languages under two types: language and languages.low-levelhigh-levelUnit 3 Computer Language and Programming161.Machine Languages In machine languages, instructions are written as sequences of 1s and 0s, called bits, that a computer can understand directly. An instruction in mac

18、hine language generally tells the computer four things:1.機器語言 在機器語言中，指令被寫成計算機能夠直接理解的，稱作比特的，1和0序列。一條機器語言指令一般告訴計算機4件事：定語從句定語從句Unit 3 Computer Language and Programming17(1)where to find one or two numbers or simple pieces of data in the main computer memory (Random Access Memory, or RAM), (2)a simple o

19、peration to perform such as adding the two numbers together,(3)where in the main memory to put the result of this simple operation, and (4) where to find the next instruction to perform.（1）到計算機主存（隨機存儲器）的什么位置去找一兩個數(shù)字或簡單的數(shù)據(jù)片；（2）要執(zhí)行的簡單操作，如將兩個數(shù)字相加；（3）在主存的什么位置存放該簡單操作的結(jié)果；（4）到什么位置去找下一條要執(zhí)行的指令。Unit 3 Computer

20、 Language and Programming18While all executable programs are eventually read by the computer in machine language, they are not all programmed in machine language.盡管所有的可執(zhí)行程序最終都是以機器語言的形式被計算機讀入的，但它們并非都是用機器語言編寫的。 讓步狀語從句讓步狀語從句Unit 3 Computer Language and Programming19It is extremely difficult to programm

21、ed in machine language because the instructions are sequence of 1s and 0s.extremelykstri:mliadv.極端地；非常；直接用機器語言編程極端困難，因為指令是0和1的序列。原因狀語從句原因狀語從句形式主語，沒有實際含義形式主語，沒有實際含義Unit 3 Computer Language and Programming20A typical instruction in a machine language might read 10010 1100 1011 and mean add the content

22、s of storage register A to the contents of storage register B.registerredst(r) n.登記，注冊；記錄；登記薄；自動記錄器；計算機寄存器一條典型的機器語言指令可能寫成100101100 1011，意思是把存儲寄存器A的內(nèi)容加到存儲寄存器B的內(nèi)容中。Unit 3 Computer Language and Programming21Fill the blanksA(n) language is a low-level language in binary code that a computer can understa

23、nd and execute directly.machineUnit 3 Computer Language and Programming222. High-Level Languages High-level languages are relatively sophisticated sets of statements utilizing words and syntax from human language.2.高級語言 高級語言是相對復(fù)雜的一系列語句，它們使用來自人類語言的詞匯和句法?，F(xiàn)在分詞短語做定語現(xiàn)在分詞短語做定語Unit 3 Computer Language and

24、Programming23They are more similar to normal human languages than assembly or machine languages and are therefore easier to use for writing complicated programs. These programming languages allow larger and more complicated programs to be developed faster.高級語言比匯編語言或機器語言類似于正常的人類語言，因此用高級語言來編寫復(fù)雜的程序比較容易

25、。這些編程語言可以更快地開發(fā)更大和更復(fù)雜的程序。Unit 3 Computer Language and Programming24However, high-level languages must be translated into machine language by another program called a compiler before a computer can understand them. compilerkmpal(r) n.匯編者；編輯者；編纂者；計算機編譯程序然而，高級語言必須由稱為編譯器的另外一種程序翻譯成機器語言，計算機才能理解它們。時間狀語從句時間狀

26、語從句Unit 3 Computer Language and Programming25For this reason, programs written in a high-level language may take longer to execute and use up more memory than programs written in an assembly language. 因為這個原因，與用匯編語言編寫的程序相比較，用高級語言編寫的程序可能運行時間長，占用內(nèi)存多。過去分詞短語做定語過去分詞短語做定語過去分詞短語做定語過去分詞短語做定語Unit 3 Computer L

27、anguage and Programming26Fill the blanksHigh-level languages must first be translated into a(n) language before they can be understood and processed by a computer.machineUnit 3 Computer Language and Programming273. Assembly Languages Computer programmers use assembly languages to make machine-langua

28、ge programs easier to write. 3.匯編語言 計算機程序員通過使用匯編語言，使機器語言程序比較容易編寫。Unit 3 Computer Language and Programming28In an assembly language, each statement corresponds roughly to one machine language instruction. An assembly language statement is composed with the aid of easy to remember commands. correspond

29、,krspndvi. 一致；相應(yīng)；通信roughlyrfliadv.粗略地；大體上；大致上aided n.幫助；助手；外援；輔助設(shè)備在匯編語言中，每個語句大致對應(yīng)于一條機器語言指令。匯編語言的語句是借助易于記憶的命令編寫的。Unit 3 Computer Language and Programming29The command to add the contents of storage register A to the contents of storage register B might be written ADD B, A in a typical assembly langua

30、ges statement.在一個典型的匯編語言語句中，把存儲寄存器A的內(nèi)容加到存儲寄存器B的內(nèi)容中這一命令，可能寫成ADD B, A。不定式短語做定語不定式短語做定語Unit 3 Computer Language and Programming30Assembly languages share certain features with machine languages. For instance, it is possible to manipulate specific bits in both assembly and machine languages. share featu

31、res with 與有共同特征匯編語言與機器語言具有某些共同的特征。例如，對特定的比特位進行操控，用匯編語言和機器語言都是可行的。Unit 3 Computer Language and Programming31Programmers use assembly languages when it is important to minimize the time it takes to run a program, because the translation from assembly language to machine language is relatively simple.

32、minimizemnmazvt.把減至最低數(shù)量當盡量減少程序的運行時間很重要時，程序員就使用匯編語言，因為從匯編語言到機器語言的翻譯相對簡單。定語從句，省略定語從句，省略thatUnit 3 Computer Language and Programming32Assembly languages are also used when some part of computer has to be controlled directly, such as individual dots on a monitor or the flow of individual characters to a

33、 printer.匯編語言也用于計算機的某個部分必須被直接控制的情況，如監(jiān)視器上的單個點或者單個字符向打印機的流動。Unit 3 Computer Language and Programming33Fill the blockIn an assembly language, each corresponds roughly to one machine language instruction.statementUnit 3 Computer Language and Programming34III.Classification of High-Level Languages High-l

34、evel languages are commonly classified as procedure-oriented, functional, object-oriented, or logic languages. The most common high-level languages today are procedure-oriented languages. orient:rntvt.標定方向；使向東方高級語言通常分為面向過程語言、函數(shù)式語言、面向?qū)ο笳Z言或邏輯語言。當今最常見的高級語言是面向過程語言。Unit 3 Computer Language and Programmin

35、g35In these languages, one or more related blocks of statements that perform some complete function are grouped together into a program module, or procedure, and given name such as “procedure A”.groupe together使形成組；把歸在一起在這種語言中，執(zhí)行某個完整功能的一個或多個相關(guān)的語句塊組成一個程序模塊或過程，而且被給予諸如“過程A”一類名稱。過去短語分詞作定語過去短語分詞作定語定語從句定語

36、從句Unit 3 Computer Language and Programming36If the same sequence of operations is needed elsewhere in the program, a simple statement can be used to refer back to the procedure. elsewhere,elswe(r)adv.在別處，到別處refer back to將轉(zhuǎn)回；重新提及如果在程序的其他地方需要同樣的操作序列，可以使用一個簡單的語句調(diào)回這個過程。Unit 3 Computer Language and Progr

37、amming37In essence, a procedure is just a mini-program. A large program can be constructed by grouping together procedures that perform different tasks. essenceesnsn.本質(zhì)，實質(zhì)實質(zhì)上，一個過程就是一個小型程序。一個大型程序可以通過將執(zhí)行不同任務(wù)的過程組合在一起而構(gòu)成。定語從句定語從句Unit 3 Computer Language and Programming38Procedural languages allow progra

38、ms to be shorter and easier for the computer to read, but they require the programmer to design each procedure to be general enough to be used in different situations.過程語言使程序變得比較短，而且比較容易被計算機讀取，但要求程序員將每個過程都設(shè)計得足夠通用，能用于不同的情況。不定式短語作定語不定式短語作定語Unit 3 Computer Language and Programming39Fill the blocksIn pr

39、ocedure-oriented languages, one or more related blocks of statements that preform some complete function are grouped together into a program , or procedure.moduleUnit 3 Computer Language and Programming40 Functional languages treat procedures like mathematical functions and allow them to be processe

40、d like any other data in a program. This allows a much higher and more rigorous level of program construction. treattri:t vt.處理；探討；對待；rigorousrgrs adj.嚴密的； 函數(shù)式語言像數(shù)學(xué)函數(shù)一樣對待過程，并允許像處理程序中的任何其他數(shù)據(jù)一樣處理它們。這就使程序構(gòu)造在更高、更嚴密的水平上得以實現(xiàn)。Unit 3 Computer Language and Programming41Functional languages also allow variabl

41、essymbols for data that can be specified and changed by the user as the program is runningto be given values only once. symbolsmbln.象征；標志；符號；記號specifyspesfa vt.指定exactzktadj.準確的,確切的,精密的,精確的redeclareri:dekle n.重新聲明，重新定義restate,ri:stet vt.重申；再次聲明函數(shù)式語言也允許變量在程序運行過程中可以被用戶指定和更改的數(shù)據(jù)符號只被賦值一次。定語從句定語從句Unit 3 C

42、omputer Language and Programming42This simplifies programming by reducing the need to be concerned with the exact order of statement execution, since a variable does not have to be redeclared, or restated, each time it is used in a program statement. 這樣，通過減少對語句執(zhí)行的確切順序給予關(guān)注的必要性，就簡化了編程，因為一個變量沒有必要每次在一個程

43、序語句中用到，都重新聲明或重新說明。原因狀語從句原因狀語從句Unit 3 Computer Language and Programming43Many of the ideas from functional languages have become key part of many modern procedural languages.來自函數(shù)式語言的許多思想已經(jīng)成為許多現(xiàn)代過程語言的關(guān)鍵部分。Unit 3 Computer Language and Programming44 Object-oriented languages are outgrowths of functional

44、 languages. In object-oriented languages, the code used to write the program and the data processed by the program are grouped together into units called objects. outgrowthatgr n.結(jié)果，副產(chǎn)物，生長物 面向?qū)ο笳Z言是函數(shù)式語言的發(fā)展結(jié)果。在面向?qū)ο笳Z言中，用來編寫程序的代碼和由程序處理的數(shù)據(jù)，組合成叫做對象的單元。過去分詞短語作定語過去分詞短語作定語Unit 3 Computer Language and Progra

45、mming45Objects are further grouped into classes, which define the attributes objects must have. A simple example of a class is the class Book. Objects within this class might be Novel and Short story. Objects also have certain functions associated within them, called methods. attributetribju:t n.屬性對

46、象進一步組合成類，而類則定義對象必須具有的屬性。類的一個簡單例子就是書這個類。這個類中的對象可能是小說和短篇小說。對象還有某些與其相關(guān)的功能，稱為方法。Unit 3 Computer Language and Programming46The computer accesses an object through the use of one of the objects methods. The method performs some action to the data in the object and returns this value to the computer. 計算機通過

47、使用一個對象的某種方法來訪問該對象。方法對對象中的數(shù)據(jù)執(zhí)行某種操作，然后將值返回給計算機。Unit 3 Computer Language and Programming47Classes of objects can also be further grouped into hierarchies, in which objects of one class can inherit methods from another class. The structure provided in object-oriented languages makes them very useful for

48、 complicated programming tasks.hierarchieshair:kizn.層inheritnhert vt.& vi.繼承對象的類也可進一步組合成層，而在層中一個類的對象可繼承另一個類的方法。面向?qū)ο笳Z言提供的這種結(jié)構(gòu)，使該語言對于復(fù)雜的編程任務(wù)非常有用。過去分詞短語作定語過去分詞短語作定語Unit 3 Computer Language and Programming48 Logic languages use logic as their mathematical base. A logic program consists of sets of fa

49、cts and if-then rules, which specify how one set of facts may be deduced from others, for example:factfktn.事實；實際；真相deduceddju:s vt.推論，推斷；演繹； 邏輯語言將邏輯用作其數(shù)學(xué)基礎(chǔ)。邏輯程序由事實組和“如果則”規(guī)則構(gòu)成，“如果則”規(guī)則具體說明一組事實如何可以從其他事實組中推斷出來，例如：定語從句定語從句賓語從句賓語從句Unit 3 Computer Language and Programming49 If the statement X is true, then

50、 the statement Y is false. In the execution of such a program, an input statement can be logically deduced from other statements in the program. Many artificial intelligence programs are written in such languages. 如果X語句為真，則Y語句為假。 在這樣一個程序的執(zhí)行過程中，一條輸入語句可以按照邏輯從程序中的其他語句推斷出來。許多人工智能程序使用這種語言編寫。Unit 3 Comput

51、er Language and Programming50QUESTIONWhat are the four classifications of high-level language?procedure-oriented languages面向過程語言functional languages函數(shù)式語言object-oriented languages面向?qū)ο笳Z言logic languages邏輯語言Unit 3 Computer Language and Programming51IV.Language Structure and Components Programming langua

52、ges use specific type of statements, or instructions, to provide functional structure to the program. A statement in a program is a basic sentence that expresses a simple ideaits purpose is to give the computer a basic instruction. 四、語言結(jié)構(gòu)與成分 編程語言使用特定類型的語句或指令，來給程序提供功能結(jié)構(gòu)。程序中的一個語句是表達一個簡單想法的基本句子它的目的是給計算

53、機一條基本指令。定語從句定語從句Unit 3 Computer Language and Programming52Statements define the types of data allowed, how data are to be manipulated, and the ways that procedures and functions work. Programmers use statements to manipulate common components of programming languages, such as variables and macros(mi

54、ni-programs within a program).macromkr n. 宏，宏指令語句定義所允許的數(shù)據(jù)類型、數(shù)據(jù)如何處理以及過程和函數(shù)的工作方式。程序員使用語句來操控編程語言的常見成分，如變量和宏（程序中的小程序段）。賓語從句賓語從句定語從句定語從句Unit 3 Computer Language and Programming53 Statements known as data declarations give names and properties to elements of a program called variables. Variables can be as

55、signed different values within the program. known as 被稱為declaration,deklren n. 聲明propertyprpt n.特性，屬性；財產(chǎn)，地產(chǎn)；assignsanvt.分派,分配;歸于;賦予,給予 數(shù)據(jù)聲明語句給稱為變量的那些程序元素以名稱和屬性。變量在程序中可以賦予不同的值。過去分詞短語作定語過去分詞短語作定語Unit 3 Computer Language and Programming54The properties variables can have are called types, and they incl

56、ude such things as what possible values might be saved in the variables, how much numerical accuracy is to be used in the values, accuracykjrsi n.精確（性），精度變量可以具有的屬性稱為類型，它們包括：變量中能保存哪些可能的值；這些值中使用何種程度的數(shù)值精度；定語從句定語從句(省略省略that)Unit 3 Computer Language and Programming55and how one variable may represent a c

57、ollection of simpler values in an organized fashion, such as a table or array.a collection of許多的；一堆；一批；一組fashionfn n.時尚，時裝；方式，方法以及一個變量可以如何以有組織結(jié)構(gòu)的方式如以表或數(shù)組的形式表示一組比較簡單的值。Unit 3 Computer Language and Programming56In many programming languages, a key data type is a pointer. Variables that are pointers do

58、 not themselves have values; instead, they have information that the computer can use to locate some other variablethat is, they point to another variable.在許多編程語言中，一個關(guān)鍵的數(shù)據(jù)類型是指針。指針變量本身沒有值，而是含有計算機可以用來查找某個其他變量的信息也就是說，它們指向另一個變量。定語從句定語從句定語從句定語從句Unit 3 Computer Language and Programming57 An expression is

59、a piece of a statement that describes a series of computations to be performed on some of the programs variables, such as X+Y/Z, in which the variables are X,Y and Z and the computations are addition and division. 表達式是語句的一段，用于描述要對一些程序變量執(zhí)行的一系列計算操作，如X+Y/Z，其中X、Y和Z為變量，加法和除法是計算操作。定語從句定語從句非限定性定語從句非限定性定語從句

60、Unit 3 Computer Language and Programming58An assignment statement assigns a variable a value derived from some expression, while conditional statements specify expressions to be tested and then used to select which other statements should be executed next.derivedravvt.& vi.得到，導(dǎo)出；源于，來自；賦值語句給一個變量賦予得自某個表達式