Naming rules and specifications for identifiers

Identifier is a user-defined name when programming ,  For example, the name of the class 、 The name of the method, the name of the variable, etc , All identifiers .

Naming rules and specifications of identifiers

1. Identifier can contain English letters 26 individual （ Case sensitive ）、0-9 Numbers 、$（ Dollar symbol ） and _（ Underline ） etc. .

2. Identifier cannot begin with a number .

3. Identifier cannot be a keyword .

4. Identifiers are strictly case sensitive .