C - Keywords

Keywords are reserved words in C with special meaning; you cannot use them as identifiers.

Common Keywords

auto, break, case, char, const, continue, default, do, double, else, enum, extern, float, for, goto, if, int, long, register, return, short, signed, sizeof, static, struct, switch, typedef, union, unsigned, void, volatile, while

Examples

// invalid: using a keyword as a variable name
int return = 5; // error

// valid: descriptive names
int return_code = 5;