Types of Variables

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统计学入门 Introduction to Statistics

Chapter 1: Introduction to Statistics
1
Variables
• A variable is a characteristic or condition that can change or take on different values. • Most research begins with a general question about the relationship between two variables for a specific group of individuals.
4
Types of Variables
• Variables can be classified as discrete or continuous. • Discrete variables (such as class size) consist of indivisible categories, and continuous variables (such as time or weight) are infinitely divisible into whatever units a researcher may choose. For example, time can be measured to the nearest minute, second, half-second, etc.
10
Correlational Studies
• The goal of a correlational study is to determine whether there is a relationship between two variables and to describe the relationship. • A correlational study simply observes the two variables as they exist naturally.

variables翻译

variables翻译"variables"的翻译是"变量"。

在计算机科学和数学领域中，变量是指用来存储和表示数据值的符号名称。

它们可以用来存储各种类型的数据，例如数字、字符串、布尔值等。

变量的用法和中英文对照例句如下：1. 声明变量 (Declare a variable):- 英文：We can declare a variable using the keyword "var". - 中文：我们可以使用关键字"var"来声明一个变量。

2. 初始化变量 (Initialize a variable):- 英文：To initialize a variable, we assign a value to it.- 中文：要初始化一个变量，我们需要给它赋一个值。

3. 变量的命名 (Naming variables):- 英文：It is important to choose meaningful names for variables.- 中文：为变量选择有意义的名称很重要。

4. 变量的赋值 (Assigning values to variables):- 英文：We can assign values to variables using the assignment operator "=".- 中文：我们可以使用赋值运算符"="将值赋给变量。

5. 使用变量 (Using variables):- 英文：We can use variables in calculations or to store intermediate results.- 中文：我们可以在计算中使用变量或者用它们来存储中间结果。

6. 变量的类型 (Types of variables):- 英文：In programming, variables can have different types such as integer, float, string, etc.- 中文：在编程中，变量可以有不同的类型，比如整数、浮点数、字符串等。

Categorical and Quantitative Variables：分类和定量变量

(but could also be a bar graph)
Introduction to Statistics--
3
Variables
Quantitative Variable Characteristics
• Possible responses are numerical in nature
8
Variables
Reviewing Variable Types
1. __________ (or __________) 2. __________ (or __________)
Introduction to Statistics--
9
Variables
Reviewing ________ Variables
3) Number of pairs of pants you own?
4) # of pockets on pants?
5) Size of pants? 6) Maker of the pants?
7) Length of inseam on the pants?
Introduction to Statistics--
• Possible responses are ________ in nature • Includes values for which it makes sense to do
operations like ________, ________ and ________. • Includes answers to ________/________ questions • Includes ‘________’ • Usually—best illustrated with a ________, but ___________________________________.

胡壮麟《语言学教程》第十一章Linguistics_and_foreign_language_teaching

2
1.1 Grammar

Do we teach grammar? How do we teach grammar?

As a compromise between the “purely formfocused approaches‖ and the ―purely meaningfocused‖ approaches, a recent movement called focus on form seems to take a more balanced view on the role of grammar in language learning.
15
Communicative competence

Dell Hymes
What a learners knows about how a language is used in particular situations for effective and appropriate communication. Includes knowledge of the grammar and vocabulary, knowledge of rules of speaking, knowledge of how to use and respond to different types of speech acts and social conventions, and knowledge of how to use language appropriately.

16

It is believed that language learning will successfully take place when language learners know how and when to use the language in various settings and when they have successfully cognized various forms of competence such as grammatical competence (lexis, morphology, syntax and phonology) and pragmatic competence (e.g., speech acts).

C语言英文课件2：数据类型

perimeter and the area */
}
Result： r =1.500000 l = 9.42, s= 7.07
4. DECLARATION AND INITIALIZATION
(1) DECLARATION form：
< data type> < variable name >[,< variable name2>……];
•Data is the object be processed by algorithm
•Data types in C：
integer 1.Basic Types
real(float) character enum array 2. Tectonic Types structure union 3. Pointer 4.NULL
(1) VARIABLE NAME：keep to rules for identifier
(2) MEMORY UNIT
(3) VALUE
Nonce value
In a program,we can quote variable by variable names
p
variable name
3
location
2. Sort
CONSTANTS
symbolic CONSTANTS
can be differentiated by writing format
2.3.2 VARIABLES
1. Concept
Its value can be changed during program
executing
2. Three elements of variables

自然科学 The Nature of Science

Explain how to RECORD DATA
Explain how to RECORD DATA
Data Tables • A way to record results and observations accurately • Have a descriptive title • Divided into columns & rows • Shows the independent variable • Provides a place to record the dependent variable
What is Science?
Review This slide show will present a question, followed by a slide with an acceptable answer. For some questions, there is a definite correct answer. For other questions, several answers may be correct.
What is SCIENCE?
There are several correct answers to this question; list as many as you can.
What is SCIENCE?
• A way to answer questions & solve problems • How we understand the world around us • A way or process used to investigate what is happening around you • It provides possible answers

分类变量和连续变量的统计方法

分类变量和连续变量的统计方法英文回答：Classification variables and continuous variables are two types of variables commonly encountered in statistics. Each type requires different statistical methods for analysis.Classification variables, also known as categorical variables, are variables that can be divided into distinct categories or groups. Examples of classification variables include gender (male or female), education level (high school, college, or graduate), and marital status (single, married, divorced). These variables are qualitative in nature and cannot be measured on a numerical scale.When analyzing classification variables, the most common statistical method is to calculate frequencies and percentages for each category. This helps to understand the distribution of the variable and identify any patterns ortrends. Bar charts or pie charts are often used to visually represent the data. Additionally, statistical tests such as chi-square test can be used to determine if there is a significant association between the classification variable and another variable of interest.On the other hand, continuous variables are variables that can take any value within a certain range. Examples of continuous variables include age, height, weight, and income. These variables are quantitative in nature and can be measured on a numerical scale.When analyzing continuous variables, statistical methods such as measures of central tendency (mean, median, mode) and measures of dispersion (range, variance, standard deviation) are commonly used. These measures provide information about the average value and variability of the variable. Histograms, box plots, and scatter plots are often used to visualize the distribution of the data. Additionally, statistical tests such as t-tests or analysis of variance (ANOVA) can be used to compare the means of different groups or assess the relationship between thecontinuous variable and other variables.In summary, classification variables and continuous variables require different statistical methods for analysis. Classification variables are analyzed using frequencies, percentages, and chi-square tests, while continuous variables are analyzed using measures of central tendency, measures of dispersion, and various statistical tests. Understanding the nature of the variable is crucialin selecting the appropriate statistical method for analysis.中文回答：分类变量和连续变量是统计学中常见的两种变量类型。

初中物理中常用的实验探究方法,控制变量法

初中物理中常用的实验探究方法,控制变量法1.在进行物理实验时，我们经常使用控制变量法来探究物理现象。

In conducting physics experiments, we often use themethod of controlling variables to explore physical phenomena.2.控制变量法可以帮助我们观察和分析实验结果，从而得出准确的结论。

The method of controlling variables can help us observe and analyze experimental results, and thus draw accurate conclusions.3.通过控制变量法，我们可以排除其他因素对实验结果的影响，以便更好地理解物理规律。

By controlling variables, we can eliminate the influenceof other factors on the experimental results in order tobetter understand physical laws.4.在进行实验时，我们需要明确变量的类型，并合理安排实验条件。

When conducting experiments, we need to clarify the types of variables and arrange the experimental conditions rationally.5.控制变量法要求我们只改变一个变量，而保持其他变量不变。

The method of controlling variables requires us to change only one variable while keeping the other variables constant.6.通过控制变量法进行实验，我们能够更加准确地观察到变化的规律。

jmeter变量格式

jmeter变量格式English Answer:Jmeter Variable Format.Apache JMeter is a popular open-source testing tool used for performance testing of various applications. One of the key features of JMeter is its ability to work with variables, which allows users to define and use dynamic values during test execution.Syntax of JMeter Variables.JMeter variables follow a specific syntax to identify and access their values in the test scripts. The syntax of a JMeter variable is as follows:${variable_name}。

where:${} is the variable prefix.variable_name is the name of the variable.Types of JMeter Variables.JMeter supports different types of variables, each serving a specific purpose:User-defined variables: These are variables defined by the user in the test plan or within individual samplers. They can hold any value, including strings, numbers, and objects.Pre-defined variables: JMeter provides a set of pre-defined variables that contain information about the current test run, such as the current thread number, iteration count, etc.Environment variables: These are variables defined in the operating system environment and can be accessed withinJMeter using the __P()__ function.Using JMeter Variables.JMeter variables can be used in various sections of the test script, including:Test plan: To define global variables that are accessible throughout the test.Thread group: To define variables specific to a particular thread group.Samplers: To set dynamic values for sampler parameters.Assertions: To compare actual results against expected values stored in variables.Listeners: To extract and report variable values during test execution.Example.Consider the following example to illustrate the use of a user-defined variable in JMeter:${my_variable} = "Hello World"This line defines a user-defined variable named"my_variable" with the value "Hello World." To use this variable in a sampler, you can reference it as:${my_variable}。

计算机专业英语17-Variables

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变量要先在程序中定义（或声明）之后才能使用，要给每个
you can use them, and you must give each variable a specific type. For example, you might declare one variable to have a type that allows it to hold numbers, and another variable to have a type that allows it to hold a person's name.
Lesson 16
Variables
Warm-up Exercises
1. How many types of variables are there in Java? 2. Which type is the Rectangle class? 3. What is called the initializing?
variables 变量 define（declare）定义，声明 strongly typed language 强类型语言 initializing，initialize 初始化 primitive 基本，原始

c 章节知识点总结

c 章节知识点总结This chapter provides an overview of the C programming language, its history, and its uses. It also introduces key concepts such as variables, data types, and control structures.1.1 History of C- Developed by Dennis Ritchie at Bell Labs in the early 1970s- Became popular due to its efficiency and portability- Influenced the development of many other programming languages1.2 Uses of C- Widely used in system programming, such as operating systems and device drivers- Also used in application programming, embedded systems, and game development- Known for its high performance and low-level control over hardware1.3 Building and Running C Programs- C programs are written in plain text using a text editor- Compiled using a C compiler to create an executable file- Executable files can be run on a compatible computer or device1.4 Hello World Program- Introduces the basic structure of a C program- Demonstrates the use of the "printf" function to output textChapter 2: Variables and Data TypesIn this chapter, we explore the concept of variables, data types, and the storage of data in memory. We also cover the declaration and initialization of variables, and the rules for naming variables in C.2.1 Variables- A variable is a named location in memory- Used to store data that can change during program execution- Must be declared with a data type before use2.2 Data Types- C supports various data types, such as int, float, and char- Each data type has a specific size and range of values- The choice of data type affects the memory usage and performance of a program2.3 Declaration and Initialization- Variables must be declared before they can be used- Declaration specifies the data type and name of the variable- Initialization assigns an initial value to the variable at the time of declaration2.4 Rules for Naming Variables- Variable names can consist of letters, digits, and underscores- Must begin with a letter or underscore- Case-sensitive: "myVar" and "myvar" are considered different variablesChapter 3: Control StructuresThis chapter covers the different control structures available in C, including decision-making and looping constructs. We also explore the use of conditional statements and loops to control the flow of a program.3.1 Conditional Statements- The "if" statement allows the execution of a block of code based on a condition- The "else" statement can be used to specify an alternative block of code- Nested "if" statements can be used to handle multiple conditions3.2 Switch Statement- The switch statement allows the selection of a block of code based on the value of an expression- Provides a more efficient alternative to nested "if" statements for multiple conditions3.3 Loops- The "while" loop executes a block of code repeatedly as long as the specified condition is true- The "do-while" loop is similar to the "while" loop, but guarantees that the block of code is executed at least once- The "for" loop provides a compact way to iterate over a range of values3.4 Loop Control Statements- The "break" statement can be used to exit a loop prematurely- The "continue" statement can be used to skip the remaining code in a loop iteration- The "return" statement can be used to exit a function and return a valueChapter 4: Functions and ScopeIn this chapter, we explore the concept of functions in C, including function declaration, definition, and calling. We also cover the scope of variables and the difference between local and global variables.4.1 Functions- A function is a block of code that performs a specific task- Can be declared, defined, and called within a C program- Can return a value to the calling code4.2 Function Declaration and Definition- Functions must be declared before they are called- Declaration specifies the function name, return type, and parameter list- Definition provides the implementation of the function4.3 Function Calling- Functions are called by their name followed by the argument list in parentheses- Arguments can be passed by value or by reference- The return value of a function can be stored in a variable or used directly4.4 Scope of Variables- The scope of a variable determines where it can be accessed within a program- Local variables are declared within a function and are only accessible within that function - Global variables are declared outside of any function and can be accessed by all functions in the program4.5- C also supports static and extern variables, which have different rules for scope and lifetime- The use of global variables should be minimized to avoid unintended side effects Chapter 5: Arrays and StringsThis chapter covers the use of arrays and strings in C, including array declaration, access, and manipulation. We also explore the similarities and differences between arrays and strings in C.5.1 Arrays- An array is a collection of variables of the same data type- Elements of an array are stored in contiguous memory locations- Arrays are declared and accessed using square brackets []5.2 Array Declaration and Initialization- Arrays must be declared with a specified size before use- Initialization can be done at the time of declaration or using a separate assignment statement- Arrays can also be initialized with an initializer list5.3 Array Access and Manipulation- Individual elements of an array can be accessed using their index- Elements of an array can be updated or modified using their index- The size of an array is fixed and cannot be changed during program execution5.4 Strings- A string is a sequence of characters stored as an array of characters- Strings in C are terminated by a null character ('\0')- String literals are enclosed in double quotes ""5.5 String Manipulation- C provides a variety of string manipulation functions, such as strlen, strcpy, and strcat - Strings can be accessed and manipulated using array-like operations- Care must be taken to avoid buffer overflows and other common string-related issuesChapter 6: PointersThis chapter introduces the concept of pointers in C, including pointer declaration, dereferencing, and pointer arithmetic. We also cover the use of pointers in array manipulation and function parameters.6.1 Introduction to Pointers- A pointer is a variable that stores the address of another variable- Pointers provide a way to indirectly access and modify the value of a variable- Pointers are declared using the asterisk (*) symbol6.2 Pointer Declaration and Initialization- Pointers must be declared with a specified type before use- Initialization can be done by assigning the address of a variable using the address-of (&) operator- Pointers can also be initialized with NULL to indicate that they do not point to any valid address6.3 Pointer Dereferencing- Dereferencing a pointer allows the value at the address it points to be accessed or modified- Dereferencing is done using the asterisk (*) operator- Care must be taken to ensure that pointers are properly initialized before dereferencing 6.4 Pointer Arithmetic- Pointers can be incremented and decremented to move to the next or previous memory location- Pointer arithmetic is based on the size of the data type being pointed to- Pointers can be used to iterate over arrays and manipulate memory directly6.5 Pointers and Arrays- Arrays and pointers are closely related in C- Arrays can be accessed using pointers and vice versa- Pointers provide a flexible way to access and manipulate the elements of an array6.6 Pointers and Functions- Pointers can be used as function parameters to pass data by reference- Pointers can also be used to return multiple values from a function- Care must be taken to avoid common pitfalls when using pointers in functionsChapter 7: Structures and UnionsThis chapter explores the use of structures and unions in C, including the declaration, access, and manipulation of structured data. We also cover the similarities and differences between structures and unions in C.7.1 Structures- A structure is a composite data type that groups together variables of different types- Each variable within a structure is called a member- Structures are declared using the "struct" keyword followed by a name7.2 Structure Declaration and Access- Members of a structure can be accessed using the dot (.) operator- Structures can be initialized using an initializer list or by assigning values to individual members- Structures provide a way to organize and manipulate related data7.3 Structures and Functions- Structures can be passed as function parameters to group related data- Structures can also be used to return multiple values from a function- Passing structures by reference can be more efficient than passing them by value7.4 Unions- A union is similar to a structure, but all members share the same memory location- Only one member of a union can be accessed at a time- Unions are useful for representing different types of data in a compact form7.5 Structures vs. Unions- Structures are used to group related data of different types- Unions are used to represent different interpretations of the same memory location- The choice between structures and unions depends on the specific requirements of the programChapter 8: File HandlingIn this chapter, we explore the concepts of file input and output in C, including file opening, reading, writing, and closing. We also cover the use of standard file streams and the difference between text and binary files.8.1 File Input and Output- Files provide a way to store and retrieve data from a secondary storage device- File handling in C is done using the "stdio.h" library- Files must be opened before data can be read from or written to them8.2 File Opening and Closing- Files can be opened for reading, writing, or both- The "fopen" function is used to open a file and returns a file pointer to access the file- The "fclose" function is used to close a file and release its resources8.3 Reading and Writing Files- Files can be read using functions such as "fscanf" and "fgets"- Files can be written to using functions such as "fprintf" and "fputs"- Care must be taken to handle errors and close files properly after use8.4 Standard File Streams- The "stdio.h" library provides three standard file streams: stdin, stdout, and stderr- These streams are automatically opened and available for input and output- Redirecting standard file streams allows for command-line input and output redirection 8.5 Text vs. Binary Files- Text files store data in a human-readable format using characters and newlines- Binary files store data in a raw format using bytes- Text files can be easily edited and viewed, while binary files are more efficient for storing complex data structuresChapter 9: Dynamic Memory AllocationThis chapter covers the concepts of dynamic memory allocation in C, including the use of malloc, calloc, realloc, and free. We also explore memory leaks and common pitfalls when working with dynamically allocated memory.9.1 Introduction to Dynamic Memory Allocation- Dynamic memory allocation allows a program to request memory from the heap at runtime- Dynamic memory management is done using the "stdlib.h" library- Dynamic memory is allocated and deallocated using pointer-based functions9.2 malloc and calloc Functions- The "malloc" function is used to allocate a block of memory of a specified size- The "calloc" function is used to allocate a block of memory and initialize it to zero- Memory allocated using "malloc" and "calloc" is not initialized and can contain garbage values9.3 realloc Function- The "realloc" function is used to resize a previously allocated block of memory- The contents of the original block are copied to the new block, and the original block is deallocated- Care must be taken to handle errors when using "realloc"9.4 free Function- The "free" function is used to deallocate a block of memory previously allocated using "malloc" or "calloc"- Failure to free dynamically allocated memory can result in memory leaks- Attempting to access memory after it has been freed can lead to undefined behavior 9.5 Memory Leaks and Pitfalls- Memory leaks occur when a program fails to deallocate dynamically allocated memory - Common pitfalls include dangling pointers, double-free errors, and buffer overflows- Debugging tools can be used to help identify and prevent memory-related issuesChapter 10: Preprocessor DirectivesIn this chapter, we explore the use of preprocessor directives in C, including the #include, #define, and #ifdef directives. We also cover conditional compilation and the use of header files.10.1 Preprocessor Directives- Preprocessor directives are commands that are processed by the C preprocessor before compilation- Directives begin with the # symbol and can be placed anywhere in the file- Preprocessor directives are used to include files, define constants, and conditionally compile code10.2 #include Directive- The #include directive is used to include the contents of another file in the current file- Header files typically contain function prototypes, constant definitions, and type declarations- Header files are included using the angle brackets < > for system headers and double quotes " " for user-defined headers10.3 #define Directive- The #define directive is used to define constants and macros in a C program- Macros are typically used for simple textual substitution before compilation- Macros can be used to define constant values, inline functions, and conditional compilation 10.4 Conditional Compilation- The #ifdef and #ifndef directives are used to conditionally include or exclude code based on predefined macros- Conditional compilation can be used to create platform-specific code, enable debugging features, and define feature flags- Conditional compilation can also be used to guard against multiple inclusions of header files10.5 Header Files- Header files are used to declare the interface of a module and are included in other files using the #include directive- Header files typically contain function prototypes, constant definitions, and type declarations- The use of header files promotes modularity and code reuse in C programsConclusionIn this comprehensive guide, we have covered the fundamental concepts of the C programming language. From the basic syntax and control structures to advanced topics such as pointers, structures, and file handling, this guide has provided a thorough overview of the C language.By mastering the principles outlined in this guide, you will be well-equipped to write efficient and portable C programs for a wide range of applications. Whether you are a beginner looking to learn the basics of programming or an experienced developer seeking to refresh your knowledge, this guide serves as a valuable resource for understanding and applying the principles of C programming.We hope this guide has been a helpful introduction to the C programming language. As you continue to explore the world of C programming, we encourage you to experiment, practice, and seek out additional resources to deepen your understanding and expand your skills. Happy coding!。

C语言C-2__

• Data storage
1. Review： decimal system and binary system(复习：二进制和十进制) 2. Why binary(为什么使用二进制)? 3. Review: bit and byte（复习：位和字节）
• Data storage
4. Integral data（整型数）:
• Data type
7. Character constant(字符型常量):
char c; c=‟r‟;
printf(“hello!\neverybody!”)
Special code: see page 48（特殊字符，见书48页）
• Variable initialization
float f; f=0.5; double f1,f2; f1=8.9;f2=7.3; int a=1;
0.45e2＝》0000 0000 0000 0000 0010 1101 0000 0010
• Data storage
6. Character（字符）:
Appendix 1: ASCII table(附录１:ASCII码表) Save to corresponding 1 bit integer（存为对应的一个字节整数）
• Arithmetic operator and arithmetic expression 3. Incremental and decremental operators （自增、自减运算符）
Could not apply to constants or expressions （不能用于常量和表达式） 5++, (a+b)++ Associate left to right（自右至左结合） -i++ => -(i++) ,＝>(-i)++; j=-i++; => j=-i; i++

variables

4. Concepts, indicators and variables
Concepts are converted into variables through indicators（指标） - a set of criteria reflective of a concept. Concepts Indicators Variables Decision level
1. The definition of a variable
An image, perception or concept that is capable of measurement - hence capable of taking on different values - is called a variable. In other words, a concept that can be measured is called a variable.
Cause
Change variables
Effect
Outcome variables
(dependent variables) (independent variables) Variables that affect the relationship (extraneous variables) (外在变项) Fig. Types of variables in a casual relationship
Morality(死亡率) Independent variable
The extent of the use of contraceptives（避孕） Intervening variables
Fertility (出生率) Dependent variable

戴维商务统计学第7版英文版教学课件BSFC7e_CH01

Chapter 1, Slide 5
Collecting Data Correctly Is A ritical
Task
DCOVA
▪ Need to avoid data flawed by biases, ambiguities, or other types of errors.
▪ Results from flawed data will be suspect or in error.
DCOVA
▪ A marketing research analyst needs to assess the effectiveness of a new television advertisement.
▪ A pharmaceutical manufacturer needs to determine whether a new drug is more effective than those currently in use.
Sources of data fall into five categories
DCOVA
Data distributed by an organization or an individual
The outcomes of a designed experiment
The responses from a survey
▪ An auditor wants to review the financial transactions of a company in order to determine whether the company is in compliance with generally accepted accounting principles.

英文文献及翻译：计算机程序

Computer Language and ProgrammingI. IntroductionProgramming languages, in computer sc ienc e, are the artific ial languages used to write a sequenc e of instructions (a computer program) that c an be run by a computer. Similar to natural languages, such as English, programming languages have a voc abulary, grammar, and syntax. How ever, natural languages are not suited for programming computers bec ause they are ambiguous, meaning that their vocabulary and grammatic al struc ture may be interpreted in multiple ways. The languages used to program computers must have simple logic al structures, and the rules for their grammar, spelling, and punctuation must be prec ise.Programming languages vary greatly in their sophistic ation and in their degree of versatility. Some programming languages are written to address a partic ular kind of computing problem or for use on a partic ular model of computer system. For instanc e, programming languages such as FORTRAN and COBOL w ere written to solve certain general types of programming problems—FORTRAN for sc ientific applic ations, and COBOL for business applic ations. Although these languages were designed to address spec ific categories of computer problems, they are highly portable, meaning that they may be used to program many types of computers. Other languages, such as mac hine languages, are designed to be used by one spec ific model of computer system, or even by one spec ific computer in c ertain researc h applications. The most c ommonly used programming languages are highly portable and can be used to effectively solve diverse types of computing problems. Languages like C, PASCAL and BASIC fall into this c ategory.II. Language TypesProgramming languages can be c lassified as either low-level languages or high-level languages. Low-level programming languages, or machine languages, are the most basic type of programming languages and can be understood directly by a c omputer. Machine languages differ depending on the manufacturer and model of computer. High-level languages are programming languages that must first be translated into a machine language before they c an be understood and processed by a computer. Examples of high-level languages are C, C++, PASCAL, and FORTRAN. Assembly languages are intermediate languages that are very c lose to mac hine languages and do not have the level of linguisticsophistic ation exhibited by other high-level languages, but must still be translated into mac hine language.1. Machine LanguagesIn mac hine languages, instructions are written as s equenc es of 1s and 0s, called bits, that a computer c an understand direc tly. An instruc tion in mac hine language generally tells the computer four things: (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 operation to perform, suc h 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 instruc tion to perform. While all exec utable programs ar e eventually read by the computer in mac hine language, they are not all programmed in machine language. It is extremely difficult to program directly in machine language bec ause the instructions are sequenc es of 1s and 0s. A typic al instruc tion in a mac hine language might read 10010 1100 1011 and mean add the contents of storage register A to the contents of storage register B.2. High-Level LanguagesHigh-level languages are relatively sophisticated sets of statements utilizing w ords and syntax from human language. They are more similar to normal human languages than assembly or machine languages and are therefore easier to use for writing c omplic ated programs. These programming languages allow larger and more complic ated programs to be developed faster. How ever, high-level languages must be translated into machine language by another program c alled a compiler before a c omputer can understand them. For 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.3. Assembly LanguagesComputer programmers use assembly languages to make mac hine-language programs easier to write. In an assembly language, each statement corresponds roughly to one mac hine language instruction. An assembly language statement is composed w ith the aid of easy to remember commands. The command to add the c ontents of the storage register A to the c ontents of storage register B might be written ADD B, A in a typical assembly language statement. Assembly languages share certain features w ith mac hine languages. For instance, it is possible to manipulate spec ific bits in both assembly and machinelanguages. Programmers use assemblylanguages 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. Assembly languages are also used when some part of the c omputer has to be c ontrolled direc tly, such as individual dots on a monitor or the flow of individua l c harac ters to a printer.III. Classific ation of High-Level LanguagesHigh-level languages are c ommonly c lassified as proc edure-oriented, functional, objec t-oriented, or logic languages. The most common high-level languages today are proc edure-oriented languages. In these languages, one or more related blocks of statements that perform some complete function are grouped together into a program module, or proc edure, and given a name such as “proc edure A.” If the same sequence of operations is needed elsewhere in the program, a simple statement can be used to refer bac k to the proc edure. In essence, a proc edure is just amini- program. A large program c an be c onstructed by grouping together procedures that perform different tasks. Proc edural languages allo w programs to be shorter and easier for the c omputer to read, but they require the programmer to design eac h procedure to be general enough to be usedin different situations. Func tional languages treat proc edures like mathematic al functions and allow them to be processed like any other data in a program. This allows a much higher and more rigorous level of program construction. Func tional languages also allow variables—symbols for data that c an be spec ified and changed by the user as the program is running—to be given values only once. This simplifies programming by reduc ing the need to be concerned w ith the exac t order of statement execution, sinc e a variable does not have to be redec lared , or restated, eac h time it is used in a program statement. Many of the ideas from functional languages have become key parts of many modern procedural languages. Object-oriented languages are outgrowths of functional languages. In objec t-oriented languages, the c ode used to write the program and the data proc essed by the program are grouped together into units called objec ts. Objec ts are further grouped into c lasses, which define the attributes objects must have. A simple example of a c lass is the c lass Book. Objects w ithin this c lass might be Novel and Short Story. Objec ts also have certain functions assoc iated w ith them, called methods. Thecomputer accesses an objec t through the use of one of the object’s methods. The method performs some ac tion to the data in the object and returns this value to the computer. Classes of objec ts can also be further grouped into hierarchies, in whic h objects of one class can inherit methods from another c lass. The structure provided in object-oriented languages makes them very useful for complic ated programming tasks. Logic languages use logic as their mathematic al base. A logic program consists of sets of facts and if-then rules, whic h spec ify how one set of facts may be deduced from others, for example: If the statement X is true, then the statement Y is false. In the execution of such a program, an input statement can be logic ally deduced from other statements in the program. Many artific ial intelligenc e programs are written in suc h languages.IV. Language Structure and ComponentsProgramming languages use spec ific types of statements, or instructions, to provide func tional structure to the program. A statement in a program is a basic sentenc e that expresses a simple idea—its purpose is to give the computer a basic instruction. Statements define the types of data allow ed, how data ar e to be manipulated, and the w ays that proc edures and functions work. Programmers use statements to manipulate common components of programming languages, such as variables and macros (mini-programs within a program). Statements known as data dec larations give names and properties to elements of a program c alled variables. V ariables c an be assigned different values w ithin the program. The properties variables c an have are c alled types, and they inc lude such things as w hat possible values might be saved in the variables, how much numeric al accuracy is to be used in the values, and how one variable may represent a collection of simpler values in an organized fashion, such as a table or array. In many programming languages, a key data type is a pointer. V ariables that are pointers do not themselves have values; instead, they have information that the computer can use to loc ate some other variable—that is, they point to another variable. An expression is a piec e of a statement that describes a series of c omputati ons to be performed on some of the program’s variables, such as X+Y/Z, in which the variables are X, Y, and Z and the computations are addition and division. An assignment statement assigns a variable a value derived from some expression, while c onditional statements spec ify expressions to be tested and then used to selec t whic h other statements should be executed next.Proc edure and function statements define c ertain bloc ks of code as procedures or functions that can then be returned to later in the program. These statements also define the kinds of variables and parameters the programmer c an c hoose and the type of value that the c ode will return when an expression acc esses the procedure or function. Many programming languages also permit mini translation programs c alled macros. Macros translate segments of c ode that have been written in a language struc ture defined by the programmer into statements that the programming language understands.V. HistoryProgramming languages date back almost to the invent ion of the digital c omputer in the 1940s. The first assembly languages emerged in the late 1950s w ith the introduc tion of commerc ial c omputers. The first proc edural languages were developed in the late 1950s to early 1960s: FORTRAN, created by John Bac kus, and then COBOL, created by Grac e Hopper The first functional language w as LISP, written by John McCarthy4 in the late 1950s. Although heavily updated, all three languages are still w idely used today. In the late 1960s, the first objec t-oriented languages, such as SIMULA, emerged. Logic languages bec ame w ell known in the mid 1970swith the introduction of PROLOG6, a language used to program artific ial intelligenc e softw are. During the 1970s, proc edural languages c ontinued to develop w ith ALGOL, BASIC, PASCAL, C, and A d a SMALLTALK w as a highly influential object-oriented language that led to the merging ofobjec t- oriented and procedural languages in C++ and more rec ently in JAVA10. Although pure logic languages have dec lined in popularity, variations hav e bec ome vitally important in the form of relational languages for modern databases, such as SQL.计算机程序一、引言计算机程序是指导计算机执行某个功能或功能组合的一套指令。

14a Sociolinguistics - linguistic variables

Intra-speaker variation
• Variation between speakers
• Dialects are a large-scale example of inter-speaker variation
- North America English truck, Britain English lorry - NA English French fries, British English chips - NA English apartment, British English flat
- NA English French elevator, British English lift
- Quebec French le déjeuner, France French le petit déjeuner ‘breakfast’
- Quebec le diner, France le déjeuner ‘lunch’
• 3. Social variables
Age Ethnicity Location Gender Class Identity
today
Monday
• 4. How society deals with language
Naming issue: variety and dialect
• In order to avoid the naming problem linguists use the valueneutral term variety for any subset of a language
- whale [ʍ] (voiceless labio-velar fricative) → older than 80 - floor → [r] high social class; →Ø low social class

ncl使用介绍

– – – –
T({12},{35:45},{-95:-105}) 1D arrays; monotonically increasing or decreasing Can only be assigned to a named dimension Assigned using “&” character
T&time = (/0,6,12,18,24/)
Reading data from files
For netCDF, HDF, GRIB
–
Use addfiles function
A= addfile(“tmp.nc”,”r”) K = A->variable
For fortran binary files
Untar:
–
Set NCARG_ROOT environment variable:
– –
Important resources for using and learning NCL
Main NCL home page:
–
/ncl
Contains links to documentation, examples, FAQ, ncl-talk email list, and update information
Data Types
Numeric Types
double float long integer short byte 64bits 32bits 32bits 32bits 16bits 8bits +/- ( 2.22507e-308 ) to (8.98846e+307) +/- ( 1.175494e-38 ) to (1.701411e+38) +/- ( 2.147483e+09 ) (64bit on SGI) +/- ( 2.147483e+09 ) +/- ( 32767 ) ( 0 ) - ( 255 )

C++完整(精华版)ppt课件

int main() { cout << "Don’t you just feel like a louse"; cout << endl;
cout << "To learn that your \"new\" theorem was proved by Gauss?"; cout << endl;
return 0; }
精品课件
6
6
cout
cout << expressions
cout<< “hello, world!”; cout<< 5; cout << x; cout << x+5; cout << x<<“+5=”<<x+5;
”\n”, “\t”, “ “, endl ,setw(n) setw(n): #include <iomanip.h>
A name in a C++ program
Starts with a letter, contains letters, digits, and underscores (only) x, number_of_elements, Fourier_transform, z2
Not names:
精品课件
19
19
Assignment and increment
a:
int a = 7;
7
a = 9;
9
a = a+a;
18
a += 2;
20
++a;

matlab的变量类型及其符号

matlab的变量类型及其符号英文回答：In MATLAB, variables are used to store and manipulate data. MATLAB supports various types of variables, including numeric, character, and logical types. Each variable type has its own symbol or notation to represent it.1. Numeric Variables:Numeric variables in MATLAB can hold numerical values, such as integers or floating-point numbers. They are represented by symbols like 'x', 'y', or 'num'. Numeric variables can be further categorized into integer types and floating-point types.Integer Variables: Integer variables can store whole numbers without any decimal points. For example, you can define an integer variable 'age' to store a person's age: age = 25.Floating-Point Variables: Floating-point variables can store numbers with decimal points. For example, you can define a floating-point variable 'temperature' to store the temperature in degrees Celsius: temperature = 25.5.2. Character Variables:Character variables in MATLAB are used to store text or strings. They are represented by symbols like 'name','text', or 'str'. Character variables are enclosed insingle quotes or double quotes. For example, you can define a character variable 'name' to store a person's name: name = 'John Smith'.3. Logical Variables:Logical variables in MATLAB can hold only two values: true or false. They are represented by symbols like 'flag', 'isTrue', or 'logical'. Logical variables are often used in conditional statements or logical operations. For example, you can define a logical variable 'isPositive' to check ifa number is positive: isPositive = (num > 0).中文回答：在MATLAB中，变量用于存储和操作数据。