Re-reading of the C programming language (1): Preface

I've read K&r's C programming language before, but I haven't written my reading notes. This time I want to seriously read the "C programming language", known as the C language Bible. As the book says, C is not a large language, nor does it require a very thick book to describe. So this reading note also wants to use a concise way to record the important points of knowledge in C language.

(1) The C language was originally designed and implemented by Deninis Ritchie in 1973.

(2) The C language is developed on UNIX systems and is written in C, whether it is the UNIX system itself or most of the programs running on it.

(3) because the C language is suitable for writing compilers and operating systems, it is called "System programming Language".

(4) The variables in C can be valid only within the function, or outside of the function, but only in one source file, and in the whole program.

(5) The pre-processing phase of the compilation will replace the program text with other source files and conditional compilation.

(6) C language is a relatively "low-level" language, which means that the C language can handle most computers can handle the object. such as characters, numbers, addresses.

(7) In addition to the static definitions and stacks provided by local variables of the function, the C language does not define any memory allocation tools, nor does it provide heap and useless memory reclamation tools.

(8) The C language itself does not provide input/output functions.

(9) The C language maintains the original design idea that programmers understand what they are doing, and the only requirement is that programmers express their intentions clearly.

(10) For a large number of programming applications, C language is recognized as a very efficient, strong expression of language.

(11) Practical programming is a good way to learn a new language.

(12) The standard library provides a common interface for interacting with the operating system. This library is defined by the ANSI standard, which means that all C-enabled machines will support it. So programs that use this library to perform input, output, or other operations that access the operating system can run on different machines without modification.

Re-reading of the C programming language (1): Preface