C Language Tutorial: First lecture-Computer language overview

When the word "language" is mentioned, many people will think of "English", "Chinese", "French", "Korean", "Japanese" and other languages, which are created to allow people to communicate with each other.

The same is true between people and computers, and if we want to make computers work according to our ideas, we also need to communicate with computers, and the language that allows people to communicate with computers is "computer language".

Computer language is divided into three main categories: machine language, assembly language and high-level languages.

(1) Machine language: Machine language is also called "Binary code Language", which is a collection of machine instructions. A machine instruction is an instruction consisting of a binary number consisting of "0" and "1". A program written directly in machine language is characterized by a computer that can be directly identified without any need for translation.

(2) Assembly language: Because the machine instruction is composed of binary number, it makes the machine instruction has the disadvantage of inconvenient memory. Therefore, the direct use of machine language written out of the program inconvenient to check errors, inconvenience maintenance. In order to alleviate the difficulty of programming in machine language, people began to use "assembly instructions" consisting of English words and various symbols instead of machine instructions, and no longer cared for specific binary encodings. In this way, the complex machine language becomes a simple and straightforward assembly. Programs written in assembly language are easier to read and understand than programs written in machine languages. However, the computer cannot recognize the program written directly in assembly language, so the program written in assembly language needs to be translated before it can be executed by the computer.

(3) High-level language: Because the assembly language relies heavily on the hardware system, the portability of programs written in assembly language is very low. And because assembly instructions that compose assembly language correspond to machine instruction one by one, the number of assembly instructions can be very large. In this way, people feel that assembly language is also very inconvenient to use. In order to change these problems, people designed a "high-level language." The "high-level language" is relative to the machine language and assembly languages of these "low-level language". The grammatical form of high-level language is closer to human language, and does not depend on hardware system, it has good portability and is easy to understand and use. At present, the world has a large impact, the use of more common high-level languages are: C, C + +, VB, Delphi, Java, Pascal, Fortran, Basic and so on. Programs written directly in high-level languages cannot be recognized by computers, so we also need to translate programs written directly in high-level languages to allow computers to execute.

Next: The development history of C language

C Language Tutorial: First lecture-Computer language overview