Chapter I. Computer LANGUAGE classification

I. Introduction to the Basics of computer

1, programming language classification and comparison:

(1) Machine language:

A, definition: because the computer can only accept binary code, so the instructions described in binary code 0 and 1 are called machine instructions, the set of all machine instructions constitute the machine language of the computer. belongs to a low-level language.

B, advantages: the fastest execution.

C, Disadvantages: The lowest level, the most complex, the most difficult to develop.

(2) Assembly language:

A, definition: assembly language in essence and machine language is the same, are directly to the hardware operation, but the instruction uses the abbreviation of the English identifier, easier to identify and memory.

B, advantages: Execution speed is relatively fast.

C, Disadvantages: Relatively low-level, complex, difficult to develop.

(3) Advanced language:

A, a number of machine-related instructions to synthesize a single instruction, remove the specific operation but not related to the completion of the details of the work, greatly simplifying the instructions in the program. High-level language is not specific to a language, including a variety of programming languages, such as c,c++,java,python,matlab,go,php and so on. Because a program written by a high-level language cannot be recognized directly by the computer, it must be performed by a translator, so the high-level language is divided into interpreted and compiled languages according to the different converters.

(i) Interpreted language: python,java,ruby,php, etc. It is equivalent to carrying a translation officer, equivalent to the present "simultaneous translation". First, the user invokes the interpreter and executes the source code file. The interpreter then interprets the source-code file edge as a machine language, which is executed by the CPU. Execution process

(a) Advantages: natural cross-platform, can be modified at any time, immediately effective, after changing the source code, directly run to see the results.

(b) Cons: Rely on the interpreter, inefficient operation, much slower than the compiler type.

(b) Compiled language: C,c++,delphi and so on. Before executing the source file, compile the source code into the target code (machine language), once and for all. First compile the source code into executable program, then execute executable program file, run the process

(a) Advantages: faster execution.

(b) Disadvantage: Poor cross-platform, modify the source files, need to recompile and execute. Different operating systems call the underlying machine language, which requires different machine code generation for different systems.

Chapter I. Computer LANGUAGE classification