The understanding of C language

C language is a general-purpose structured language. Its universality and unrestricted nature make it more popular and effective for many programmers. Whether it is the system software or data processing, non-numerical calculation, etc., can be very convenient to use C language.

The main features of C language:

1: Concise, compact, flexible.

2: Modular, structured.

3: Strong portability.

4: Generate target code high quality, program execution efficiency.

c The composition of the program:

A C program is usually made up of functions, statements, annotations, pre-processing commands, and other basic parts.

1: Function

C programs are composed of functions, a C program and only one main function. You can also have a main function that consists of several other functions, all of which are executed directly or indirectly by the main function.

2: Statement

C Language Program code, a statement can be divided in a few lines, one line can also write multiple statements, each statement separated by semicolons, each statement followed by a semicolon separated. In a function, statements are divided into declaration statements and execution statements. 、

3: Notes

Note of the program is very important in the process of writing a program, a non-annotated program like a non-description of the software, so in the process of writing a program, writing a good comment is a very good habit.

4: Preprocessing command

Common preprocessing commands are divided into two types

The ①include command, also called the file contains a command, is to introduce a text file into the program at that point where the text file contains definitions of many functions.

② #define用来定义一个符号常量. Example: #define PI 3.1415923 with pi instead of 3.1415926 in the file

The understanding of C language