programming language commonly known as "computer language", the variety is very much, in general, can be divided into machine language, assembly language, high-level language three categories. Computer every action, a step, is in accordance with the computer language has been programmed to execute, the program is the computer to execute the set of instructions, and the program is all in the language we have mastered to write. So people have to control the computer. Be sure to issue commands to the computer through computer language. There are two types of programming languages available today: assembly language and high-level languages.
The purpose of the programming language is to use human language to control the computer and tell the computer what we are going to do. Human language is easy to understand, easy to learn, and highly efficient to develop.
The popular programming languages are C, C + +, Java, C #, PHP, JavaScript, etc., and each language has its own areas of expertise, such as:
C language is an earlier development of a high-level language, and many later languages are based on C language design;
Java and C # can not only be used to develop software, but also to develop web site daemon;
PHP is mainly used to develop the background of the website program;
JavaScript is primarily responsible for the front-end work of the site.
Programming language is similar to human language, we can easily understand its meaning. But at the bottom of the computer hardware, all the data is represented by 1 and 2 high and low levels, the computer can only recognize these two levels. So, how can "human language" be converted into "0&1 language"? This is the focus of the programming language.
Each programming language has a detailed set of specifications that explain how the language is translated into machine language (sequences 0 and 1), which we call syntax. The syntax explains how many "words" and "sentences" there are in a programming language, respectively.
Each language has a corresponding compiler, the compiler can recognize "words" and "sentences", the programming language "translated" Into the machine can recognize the language, namely 0 and 1 sequence. This process is called compiling.
All programming languages are a principle that uses languages that humans can read to write source code, and then compiles the source code into a machine-readable language (0 and 1 sequences), called the target code.
A programming language is a set of specifications that specifies the syntax by which the compiler compiles source code into target code.
Types of programming languages
Assembly
The language of assembly language is the same as that of the machine, which is directly to the hardware, but the instruction adopts the English abbreviation identifier, which is easier to recognize and remember. It also requires programmers to write each step of a specific action in the form of a command. Assembler usually consists of three parts: instruction, pseudo-instruction and macro-instruction. Each instruction in the assembler can only correspond to a very subtle action in the actual operation. For example, mobile, self-increment, so the assembly source program is generally more lengthy, complex, error-prone, and the use of assembly language programming requires more computer expertise, but the advantages of assembly language is also obvious, with assembly language can be done by the general high-level language can be achieved, and the source program generated by the assembly of the executable file is not only smaller, and execution speed quickly.
scripting language
scripting language (script language,scripting language,scripting programming Language) is a computer programming language created to shorten the traditional authoring-compile-link-run (edit-compile-link-run) process. This naming originates from a script "screenplay", which repeats the dialog box verbatim each time it is run.
Early scripting languages are often referred to as bulk processing languages or work control languages. A script is usually interpreted as running rather than compiled.
While many scripting languages go beyond the automation of simple tasks in computers, they are still known as scripts when they are mature enough to write elaborate programs. Almost every computer system has a scripting language at every level. Including the operating system layer, such as computer games, Web applications, word processing documents, network software and so on. In many ways, high-level programming languages and scripting languages intersect, and there is no clear boundary between them.
Script programming is faster and script files are significantly smaller than similar C program files. This flexibility is at the expense of execution efficiency. Scripts are often interpreted as executing, and may be slow and run with more memory. In many cases, such as writing some dozens of-line small scripts, the writing advantage of this is far more than the disadvantage of the runtime, especially when the current programmer's salary divorve and hardware costs are low.
Scripting language is an explanatory language, such as Python, Vbscript,javascript,installshield script,actionscript, and so on, it is not like c\c++, etc. can be compiled into binary code, in the form of executable files exist.
Machine language
Since the computer can only accept binary code, the instructions described in binary code 0 and 1 are called machine instructions, and the set of all machine instructions forms the machine language of the computer, and the program programmed in machine language is called the target program. Only the target program can be directly recognized and executed by the computer. But the machine language program has no obvious characteristics, difficult to remember, inconvenient to read and write, and depends on the specific machine, the limitations are very large, machine language belongs to the low-level language.
Advanced language
High-level languages are the choice of most programmers. Compared with assembly language, it not only synthesizes many related machine instructions into a single instruction, but also removes details related to the operation but not relevant to the completion of the work, such as the use of stacks, registers, etc., which greatly simplifies the instructions in the program. At the same time, because of the omission of a lot of details, programmers do not need to have too much expertise.
The high-level language is mainly relative to the assembly language, it does not refer specifically to a specific language, but includes many programming languages, like the simplest programming language Pascal language is also a high-level language.
High-level language programming programs can not be directly recognized by the computer, must be converted to be executed, according to the conversion can be divided into two categories:
Interpretation class: The execution is similar to our daily life "simultaneous translation", the application source code on the other side by the corresponding language interpreter "translated" Into the target code (machine language), side execution, so inefficient, and can not generate independent executable files, the application can not be separated from its interpreter, However, this approach is more flexible and can be dynamically adjusted and modified by the application. such as the QBasic language of earlier periods.
Compile class: Compile refers to the program source code "translated" Into the target code (machine language) before the application of the source program, so its target program can be independently executed from its language environment, the use is more convenient and efficient. However, once the application needs to be modified, the source code must be modified, and then recompiled to generate a new target file (*. obj, which is the obj file) to execute, only the target file without source code, modification is inconvenient.
What is a programming language
