Common programming languages

Computer language can be divided into machine language, assembly language, high-level languages. We use the computer language to write the programs we need, and then program the execution of each step of the computer. It can be said that computer language is the "cornerstone" of software engineering. Let me briefly introduce the programming language commonly used in project development.

Machine language: Machine language is a set of machine instructions that can be directly identified and executed by a computer using binary code. It is the computer's designer through the computer's hardware structure gives the computer the operation function. Machine language has the characteristics of flexibility, direct execution and fast speed. Different models of computers whose machine language is not interlinked, according to a computer machine instructions compiled program, can not be executed on another computer. An instruction is a statement of the machine language, it is a set of meaningful binary code, the basic format of the instruction, such as the Operation Code field and the Address Code field, where the operation code indicates the operation of the instruction and function, the address code gives the address of the operand or operand. In machine language programming, programmers first memorize all the instruction code and the meaning of the code used by the computer. When you hand-program, programmers have to handle each instruction and each data storage allocation and input and output, but also have to remember in the programming process of each step used in the state of the work unit. This is a very tedious task. The time it takes to write a program is often dozens of times times or hundreds of times times the actual run time. Furthermore, the programmed programs are all 0 and 1 instruction codes, which are poor in visibility and error prone. In addition to the computer manufacturer's professionals, the vast majority of programmers are no longer learning machine language.

Assembly Language: assembly language is a low-level language for computers, microprocessors, microcontrollers, or other programmable devices, also known as symbolic languages. In assembly language, a mnemonic is substituted for the operation code of a machine instruction, and an address symbol or label is substituted for the address of an instruction or operand. In different devices, assembly languages correspond to different sets of machine language instructions, which are converted into machine instructions through the assembly process. Generally speaking, the specific assembly language and the specific machine language instruction set is one by one corresponding, the different platforms can not be directly ported. Many assembler programs provide additional support mechanisms for program development, assembly control, and auxiliary debugging. Some assembly-language programming tools often provide macros, which are also known as Macro assemblers. Assembly language is not widely used in program design like most other programming languages. In today's practical applications, it is often used on the ground floor, hardware operations and high-demand program optimization scenarios. Assembly language is required for drivers, embedded operating systems, and real-time running programs.

Third generation of advanced programming languages:

1. C Language:

C language is a general-purpose computer programming language, widely used. The goal of the C language is to provide a programming language that compiles, processes low-level memory, produces a small amount of machine code, and can run without any running environment support in an easy way. Although the C language provides a lot of low-level processing features, but still maintain a good cross-platform features, a standard specification written in the C language program can be compiled on many computer platforms, and even include some embedded processors (microcontroller or MCU) and supercomputers and other operating platforms. In the 1980s, in order to avoid the differences in C language grammar used by the development companies, a complete set of international standard grammar, called ANSI C, was set up by the American National Standards Bureau for C language, as the original C language standards.  2, Pascal: Professor Niklaus Wirth, from the Federal University of Zurich, Switzerland, was designed and founded in the late 60. In 1971, Professor Nickeraus Walls (N.wirth) of the Swiss Federal Institute of Technology invented another simple and clear computer programming language, which is the Pascal language named after the computer pioneer Pascal. Pascal's grammar was rigorous, and was widely welcomed in the first place, and quickly spread from Europe to the United States. Pascal is the first structured programming language to emerge, with rich data types and simple and flexible operation statements. Pascal is named after the French mathematician and philosopher Bleze Pasca, based on the ALGOL programming language. Wirth later developed a Pascal-like Modula-2 and Oberon. Prior to the development of Pascal, Tevez developed the language Euler and then developed the algol-w. Initially, Pascal was largely but not completely designed to teach students structured programming. Many generations of students have used Pascal as an introductory language for undergraduate courses. The Pascal variant is also increasingly used in all fields from research projects to PC games and embedded systems. The updated Pascal compiler exists in areas where it is widely used. The Gcc,gnu C compiler was originally written in a dialect pastel of Pascal (see Gcc# Overview). Pascal is the high-level language used in Apple Lisa and early Mac development, and the first part of the Macintosh operating system was manually translated from the Pascal source code into Motorola 68000 assembly language. The popular typesetting system Tex was written by Gartner using the original literature programming system web based on Dec pdp-10 Pascal, and the application like Total Commander was written using Delphi (that is, Object Pascal). Object Pascal is still widely used to develop Windows applications such as Skype.  fortran: Derived from the "formula flippingThe abbreviation "(English: Formulatranslation) is a programming language. It is the world's first high-level computer programming language, widely used in science and engineering computing field. Fortran language plays an important role in the field of numerical, scientific and engineering computing with its unique functions. Versions prior to Fortran 90 are known as FORTRAN (all uppercase letters), and are written in Fortran 90 and later versions (with the first letter capitalized). Fourth generation advanced programming languages: 1, C + +: An object-oriented programming language developed on the basis of C language, widely used; C + + supports multiple programming paradigms-object-oriented programming, generic programming, and procedural programming. The latest official standard C + + was announced on August 18, 2014. Its wide range of programming, often used in system development, engine development and other applications, is by far the most popular programmers have been the most powerful programming language, support classes: class, encapsulation, overloading and other features.  2, Java:java is a generic term for the Java object-oriented programming language (hereinafter referred to as the Java language) and the Java platform introduced by Sun Microsystems Corporation. Co-developed by James Gosling and co-workers, and was formally launched in 1995. Originally known as Oak, Java was designed for embedded chips in consumer electronics in the 1991. Renamed Java in 1995 and redesigned to develop Internet applications. Java-enabled HotJava browser (Java applet support) shows the charm of Java: Cross-platform, dynamic web, Internet computing. Since then, Java has been widely accepted and promoted the rapid development of the web, commonly used browsers support Javaapplet. Java technology, on the other hand, is constantly being updated. Since the advent of Java is very popular, rapid development, the C + + language to form a strong impact. In the global cloud computing and mobile Internet industry environment, Java has a significant advantage and broad prospects. 2010 Oracle Company acquires Sun Microsystems.  3, C #: Microsoft publishes an object-oriented, high-level programming language that runs on the. NET framework. And is scheduled to debut on the Microsoft Career Developer Forum (PDC). C # is the latest achievement of Microsoft researcher Anders Hejlsberg. C # looks surprisingly similar to Java, and it includes processes such as single inheritance, interfaces, almost the same syntax as Java, and the process of compiling into intermediate code. But C # differs significantly from Java in that it draws on a feature of Delphi, which is directly integrated with the COM (Component Object model), and it is Microsoft Corporation.NET Windows network framework. C # is a secure, stable, simple, elegant, object-oriented programming language derived from C and C + +. It inherits the power of C and C + + while removing some of their complex features (such as no macros and multiple inheritance not allowed). C # combines VB's simple visualization and C + + 's high operational efficiency with its powerful operational capabilities, elegant grammatical style, innovative language features and convenient component-oriented programming support. The preferred language for net development. C # is an object-oriented programming language. It allows programmers to quickly write various Microsoft-based. NET platform for applications, MICROSOFT. NET provides a range of tools and services to maximize the development and utilization of computing and communications. C # makes it possible for C + + programmers to develop programs efficiently, and because they can invoke native native functions written by C + +, there is no loss of the powerful functionality that C + + has in the original. Because of this inheritance, C # and C + + have great similarities, and developers familiar with similar languages can quickly move to C #.  4, Python: An object-oriented, interpreted computer programming language, invented by Guido van Rossum in 1989, the first public offering was released in 1991. Python is purely free software,  source code and interpreter CPython follow  GPL (gnu general public License) protocol  . Python syntax is simple and clear, and one of the features is to force whitespace (white space) to be indented as a statement. Python has a rich and powerful library. It is often nicknamed the glue language and is able to easily connect a variety of modules made in other languages, especially in C + +. A common application scenario is to use Python to quickly generate a prototype of the program (sometimes even the final interface of the program), and then to the parts of which [2]   has special requirements, in a more appropriate language rewrite, such as 3D game Graphics Rendering module, performance requirements are particularly high, you can use C /c++ is overridden and then encapsulated as an extension class library that Python can invoke. It is important to note that you may need to consider platform issues when you use the Extended class library, and some may not provide cross-platform implementations.   Structured Query Language: SQL: A special purpose programming language, a database query and programming language for accessing data and querying, updating, and managing relational database systems, as well as the extension of database script files. Structured Query language is a high-level, non-procedural programming language that allows users to work on high-level data structures. It does not require the user to specify the method of storing data, and does not require the user to understand the specific data storage methods, so theDifferent database systems with completely different underlying structures can use the same Structured Query language as the interface for data entry and management. Structured Query Language statements can be nested, which gives it great flexibility and powerful functionality. In October 1986, the National Standards Association of America normalized SQL as the standard language for the relational database management system (ANSI X3. 135-1986), with the support of the International Standards Organization (ISO) in 1987. However, in the course of practice, various database systems have made some modifications and extensions to the SQL specification. So, in fact, the SQL between different database systems cannot be completely common to each other.   Web design and development language: 1, HTML: Super-text Markup language is a standard universal markup language under an application, is also a specification, a standard,   Hypertext Markup Language   It uses marker symbols to mark the page to be displayed in the various parts. The Web page file itself is a text file, by adding a marker in a text file, you can tell the browser how to display the content (such as: How the text is handled, how the picture is arranged, how the image is displayed, etc.). The browser reads the Web page file sequentially, and then interprets and displays the contents of its tag according to the marker, and the mark that writes the error does not indicate its error, and does not stop its interpretation execution, the author can only display the effect to analyze the cause of the error and the error site. It is important to note, however, that for different browsers, there may be different interpretations of the same marker, which may result in differing displays.  2, ASP: The early development of web programs is so complicated that it is necessary to write a lot of C code to make a simple dynamic page. Microsoft introduced a Web application Development technology ASP in 1996 to replace the CGI standard for programmable extensions of Web servers. The main function of ASP is to combine scripting language, HTML, component, and Web database access to form an application that can run on the server, which can generate the corresponding HTML page and send it back to the browser based on the request from the browser-side. ASP enables you to create Web applications that use HTML Web pages as a user interface and that enable you to interact with the database.  3, PHP: A common open source scripting language. The grammar absorbs the C language, Java and Perl features, is conducive to learning, widely used, mainly for the field of web development. PHP's unique syntax mixes the syntax of C, Java, Perl, and PHP's own creation. It can execute Dynamic Web pages more quickly than CGI or Perl. Dynamic pages made in PHP are compared to other programming languages, and PHP is executed in HTML (an application under the standard Universal Markup Language) and executed more efficiently than CGI, which generates HTML markup entirely.much higher; PHP can also execute post-compilation code that compiles to encrypt and optimize code runs, making code run faster.  

Common programming language