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What are the c language identifiers?
Identifiers can only be letters (A~Z, a~ z), numbers (0 to 9), and underscores (), and the first character must be a letter or underscore. For example, correct identifiers: abc, a1, prog_to. In C language, identifiers are divided into three categories: keywords, predefined identifiers, and user-defined identifiers. [Recommended tutorial: C video tutorial]
Note on identifiers in C language:
cannot be used C language keywords are used as user identifiers, such as if, for, while, etc.
The length of the identifier is determined by the compilation system on the machine. The general limit is 8 characters (Note: The 8-character length limit is The C89 standard and the C99 standard have expanded the length. In fact, most industry standards are longer).
Identifiers are case-sensitive, that is, they are strictly case-sensitive. Generally use lowercase for variable names and uppercase for symbolic constants.
Identifier naming should be so that "the meaning is known by the name", for example, length (foreign language: length), sum, total (foreign language: sum), pi (foreign language: pi)...
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