What are compiled languages and interpreted languages?

First, what are compiled languages and interpreted languages ？

        Computers can't understand high-level languages , Can not directly execute high-level language , It can only understand machine language directly , So if a program written in any high-level language wants to be run by a computer , It has to be converted into computer language , That's machine code .

 

        Computers can't understand high-level languages , Can not directly execute high-level language , It can only understand machine language directly , So if a program written in any high-level language wants to be run by a computer , It has to be converted into computer language , That's machine code . There are two ways of this transformation ：

1. compile

2. explain

Therefore, high-level languages are also divided into compiled languages and interpreted languages .

The main difference is that , The former can run on the platform after compiling the source program , The latter is compiled during runtime . So the former runs fast , The latter has good cross platform performance .

Compiler language

        Use a special compiler , For a specific platform , Compile the high-level language source code into machine code that can be executed by the hardware of the platform , And packaging into the platform can identify the executable program format .

characteristic

        Before a program written in a compiled language is executed , A special compilation process is needed , Compile the source code into a machine language file , Such as exe File format , When you want to run again later , You can use the compilation results directly , Such as direct operation exe file . Because it only needs to be compiled once , You don't need to compile later , So compiler language is efficient .

summary

1. Compile into platform related machine language files at one time , The runtime is detached from the development environment , High operational efficiency ;

2. Platform specific , Generally, it can't be ported to other platforms ;

3. The existing C、C++、Objective All of them belong to compiler language .

 

Explanatory language

Use a special interpreter to interpret the source program line by line into a specific platform machine code and execute it immediately . It is only when the code is executed that the interpreter dynamically translates and executes line by line , Instead of translating before execution .

characteristic

Interpretive languages don't need to be compiled in advance , It directly interprets the source code into machine code and executes it immediately , So as long as a platform provides the corresponding interpreter can run the program .

summary

1. Every time an interpreted language runs, it needs to interpret the source code as machine code and execute it , Low efficiency ;

2. As long as the platform provides the corresponding interpreter , You can run the source code , So it is easy to transplant the source program ;

3.Python Etc. belong to explanatory language .

Compiled and interpreted , Both have advantages and disadvantages

The former is due to the fast execution of the program , Lower system requirements under the same conditions , So it's like developing an operating system 、 Large applications 、 The database system uses it all the time , image C/C++、Pascal/Object Pascal（Delphi） They are all compiled languages , And some web script 、 Server script and auxiliary development interface do not require high speed 、 Programs that have certain requirements for compatibility between different system platforms usually use interpretative languages , Such as Java、JavaScript、VBScript、Perl、Python、Ruby、MATLAB wait .

About java

Java Different from other languages . because java There are different for different platforms JVM, Cross platform implementation . therefore Java Language has a saying that compilation runs everywhere .

1. You can say it's compiled ： Because of all the Java The code is compiled ,.java There is no use without compilation . 

2. You can say it's interpretive ： because java The code cannot be run directly after compilation , It is interpreted to run in JVM Upper , So it's interpreted to run , That's even the explanation . 

3. however , current JVM For efficiency , There are some. JIT Optimize . It will .class The binary code of is compiled into local code to run directly , therefore , It's compiled again .

 

 

Personally think that ,java It's an interpretive language , Because though java You also need to compile , Translate it into .class file , But it's not a machine recognizable language , It's bytecode , In the end jvm The explanation of , In order to execute , It's also java Cross platform reasons . So I said java It's compiled , It's also explanatory , But if it has to be classified , From a conceptual definition , I'm afraid java It should be put into explanatory language . 

Compiled languages include ：C、C++、Delphi、Pascal、Fortran 

Explanatory languages include ：Java、Basic、javascript、python