C language-keywords, identifiers (zhi), annotations

first, the key word1. keywords

Is the C language provides the special meaning of the symbol, also known as the reserved word, in the C language in a total of 32 keywords, they were given a special meaning. Such as: main, int, struct, and so on.

2. Characteristics of keywords

1> are all lowercase

2> displays special colors in the editing tool, such as highlighting in Xcode, usually purple-brown.

Second, identifiers1. Identifiers

is to customize some of the symbols and names in the program. To differentiate from keywords: the keyword is the symbol that is provided by the C language by default, and the identifier is customized by the programmer.

2. The role of identifiers

The 1> identifier is the symbol used to identify something, and the purpose is to separate it.

There may be multiple functions and variables in the 2> C language, and each function and variable will be given a different name in order to differentiate them.

3. Naming conventions and principles

1> can only be made up of 26 letters in uppercase and lowercase, 10 Arabic numerals 0~9, and an underscore _

2> Strictly case-sensitive

3> cannot start with a number

4> cannot use keywords as identifiers

5> identifiers are as meaningful as possible to facilitate reading and communication

6> If the identifier contains more than one word, use the hump to identify it (except to start the first word, the first letter of each word is capitalized): FirstName, MyCount

Third, comments1. Notes

Note In computer language has a very important role, as the name implies, is the annotation, meaning.

2. The role of annotations

1> improves code readability and facilitates communication between programmers

2> Check Code

3> Troubleshooting Errors

3. Annotation Types

1> Single-line comment://

* Single-line comment starts with two forward slash//, can only comment one line, starting at the end of the line with a slash

* Comment can be written anywhere, inside and outside of the function, behind each statement

2> Multi-line Comment:/* */

* The multiline comment starts with/* and ends with */, the contents of * * and/* are commented

4. Nested use of annotations

1> Single-line comments can nest single-line comments, multiline comments

wow haha//Oh OH

/* Do you know how to use it? */

2> Multiline comments can nest single-line comments

/*

This is a single-line comment that is nested

This is also a single-line comment that is nested

*/

3> Multiline comments cannot nest multiple lines of comments

/*

/* This nesting is wrong */

*/

C language-keywords, identifiers (zhi), annotations