enum in struct by c-CodePudding

I have segment of code which from C by compiling in C . But it fail. Does anyone know to modify?

/* types of expressions */
typedef enum
{
    JAM_ILLEGAL_EXPR_TYPE = 0,
    JAM_INTEGER_EXPR,
    JAM_BOOLEAN_EXPR,
    JAM_INT_OR_BOOL_EXPR,
    JAM_ARRAY_REFERENCE,
    JAM_EXPR_MAX

} JAME_EXPRESSION_TYPE;

enum OPERATOR_TYPE
{
    ADD = 0,
    SUB,
    UMINUS,
    MULT,
    DIV,
    MOD,
    NOT,
    AND,
    OR,
    BITWISE_NOT,
    BITWISE_AND,
    BITWISE_OR,
    BITWISE_XOR,
    LEFT_SHIFT,
    RIGHT_SHIFT,
    DOT_DOT,
    EQUALITY,
    INEQUALITY,
    GREATER_THAN,
    LESS_THAN,
    GREATER_OR_EQUAL,
    LESS_OR_EQUAL,
    ABS,
    INT,
    LOG2,
    SQRT,
    CIEL,
    FLOOR,
    ARRAY,
    POUND,
    DOLLAR,
    ARRAY_RANGE,
    ARRAY_ALL
};

typedef enum OPERATOR_TYPE OPERATOR_TYPE;

typedef struct EXP_STACK
{
  OPERATOR_TYPE     child_otype;
  JAME_EXPRESSION_TYPE type;
  long              val;
  long              loper;      /* left and right operands for DIV */
  long              roper;      /* we save it for CEIL/FLOOR's use */
} EXPN_STACK;

#define YYSTYPE EXPN_STACK      /* must be a #define for yacc */

YYSTYPE jam_null_expression = {0,0,0,0,0};//line 221

I got message:
"[Error] JAMEXP.C@221,31: invalid conversion from 'int' to 'OPERATOR_TYPE' [-fpermissive]\r\n"
"[Error] JAMEXP.C@221,33: invalid conversion from 'int' to 'JAME_EXPRESSION_TYPE' [-fpermissive]\r\n"

CodePudding user response：

C does not allow implicit conversion from int to enum. You can use static_cast. However, anyhow it would be better to spell it out explicitly, then there is no need for the cast:

YYSTYPE jam_null_expression = {ADD ,JAM_ILLEGAL_EXPR_TYPE ,0,0,0};

Note that in C there is no need for the typedefs and that there are scoped enums, which are even more restrictive and for that reason considered more safe to use.

CodePudding user response：

You cannot assign values to enums, they are just used as numbers

Example:

switch(i) // i -> int

case OPERATOR_TYPE::ADD :// 0. Index

break; case OPERATOR_TYPE::SUB:// 1. Index

break;