[C language] objective questions - knowledge points

1. Code can have comments , But it must be a valid comment ; Generally, there are requirements for the number of project notes , Not more is better ; Invalid comments are not optional , You need to delete all invalid fixations .
2. The identifier is the programmer's own name , Except for variable names , The function name will be mentioned later 、 Macro name 、 Structure name, etc , They are all identifiers . however , You can't name it casually , Comply with the specifications ;C Language policy , Identifiers can only be made of letters （A-Z, a-z）、 Numbers （0~9） And the underline （_） form , And the first character must be a letter or underscore , It can't be a number .