MISRA.ENUM.OPERAND

Expression of enum type is used in arithmetic context.

MISRA-C++ Rule 4-5-2 (required): Expressions with type ''enum'' shall not be used as operands to built-in operators other than the subscript operator [ ], the assignment operator =, the equality operators == and !=, the unary & operator, and the relational operators <, <=, >, >=.

Rationale

Enumerations have implementation-defined representation and so should not be used in arithmetic contexts.

Example

enum { COLOUR_0, COLOUR_1, COLOUR_2, COLOUR_COUNT } colour;
if ( COLOUR_0 == colour )                      // Compliant
if ( ( COLOUR_0 + COLOUR_1 ) == colour )       // Non-compliant
if ( colour < COLOUR_COUNT )                   // Compliant