C uses the uppercase letters A to Z, the lowercase letters a to z, the digits 0 to 9, and certain special characters as building blocks to form basic program elements (e.g. constants, variables, operators, expressions, etc). The special characters are listed below: + - * / = % & # ! ? ^ “ ' ~ \ | < > ( ) [ ] { } : ; . , - (blank space) (Horizontal tab) (White Space) Most versions of the language also allow certain other characters, such as @ and $ to be included with strings & comments.
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