Iterating over non-incremental Enum

Question

Before you ask, I\'ve looked and looked for this on SO, and cannot find a solid answer.

I need to be able to dynamically iterate over an enum that has non-incre

Answer 1

There are a lot of answers to this question already, but most of them are either very complicated or inefficient in that they don't directly address the requirement of iterating over an enum with gaps. Everyone so far has said that this is not possible, and they are sort of correct in that there is no language feature to allow you to do this. That certainly does not mean you can't, and as we can see by all the answers so far, there are many different ways to do it. Here is my way, based on the enum you have provided and the assumption that it's structure won't change much. Of course this method can be adapted as needed.

typedef enum {
    CAPI_SUBTYPE_NULL = 0,               /* Null subtype. */
    CAPI_SUBTYPE_DIAG_DFD = 1,           /* Data Flow diag. */
    CAPI_SUBTYPE_DIAG_ERD = 2,           /* Entity-Relationship diag. */
    CAPI_SUBTYPE_DIAG_STD = 3,           /* State Transition diag. */
    CAPI_SUBTYPE_DIAG_STC = 4,           /* Structure Chart diag. */
    CAPI_SUBTYPE_DIAG_DSD = 5,           /* Data Structure diag. */
    CAPI_SUBTYPE_SPEC_PROCESS = 6,       /* Process spec. */
    CAPI_SUBTYPE_SPEC_MODULE = 7,        /* Module spec. */
    CAPI_SUBTYPE_SPEC_TERMINATOR = 8,    /* Terminator spec. */

    CAPI_SUBTYPE_DD_ALL = 13,            /* DD Entries (All). */
    CAPI_SUBTYPE_DD_COUPLE = 14,         /* DD Entries (Couples). */
    CAPI_SUBTYPE_DD_DATA_AREA = 15,      /* DD Entries (Data Areas). */
    CAPI_SUBTYPE_DD_DATA_OBJECT = 16,    /* DD Entries (Data Objects). */
    CAPI_SUBTYPE_DD_FLOW = 17,           /* DD Entries (Flows). */
    CAPI_SUBTYPE_DD_RELATIONSHIP = 18,   /* DD Entries (Relationships). */
    CAPI_SUBTYPE_DD_STORE = 19,          /* DD Entries (Stores). */

    CAPI_SUBTYPE_DIAG_PAD = 35,          /* Physical architecture diagram. */
    CAPI_SUBTYPE_DIAG_BD  = 36,          /* Behaviour diagram. */
    CAPI_SUBTYPE_DIAG_UCD = 37,          /* UML Use case diagram. */
    CAPI_SUBTYPE_DIAG_PD  = 38,          /* UML Package diagram. */
    CAPI_SUBTYPE_DIAG_COD = 39,          /* UML Collaboration diagram. */
    CAPI_SUBTYPE_DIAG_SQD = 40,          /* UML Sequence diagram. */
    CAPI_SUBTYPE_DIAG_CD  = 41,          /* UML Class diagram. */
    CAPI_SUBTYPE_DIAG_SCD = 42,          /* UML State chart. */
    CAPI_SUBTYPE_DIAG_ACD = 43,          /* UML Activity chart. */
    CAPI_SUBTYPE_DIAG_CPD = 44,          /* UML Component diagram. */
    CAPI_SUBTYPE_DIAG_DPD = 45,          /* UML Deployment diagram. */
    CAPI_SUBTYPE_DIAG_PFD = 47,          /* Process flow diagram. */
    CAPI_SUBTYPE_DIAG_HIER = 48,         /* Hierarchy diagram. */
    CAPI_SUBTYPE_DIAG_IDEF0 = 49,        /* IDEF0 diagram. */
    CAPI_SUBTYPE_DIAG_AID = 50,          /* AID diagram. */
    CAPI_SUBTYPE_DIAG_SAD = 51,          /* SAD diagram. */
    CAPI_SUBTYPE_DIAG_ASG = 59           /* ASG diagram. */
} CAPI_SUBTYPE_E;

struct ranges_t
{
    int start;
    int end;
};
ranges_t ranges[] =
{
    {CAPI_SUBTYPE_NULL,         CAPI_SUBTYPE_NULL},
    {CAPI_SUBTYPE_DIAG_DFD,     CAPI_SUBTYPE_DIAG_DSD},
    {CAPI_SUBTYPE_SPEC_PROCESS, CAPI_SUBTYPE_SPEC_TERMINATOR},
    {CAPI_SUBTYPE_DD_ALL,       CAPI_SUBTYPE_DD_STORE},
    {CAPI_SUBTYPE_DIAG_PAD,     CAPI_SUBTYPE_DIAG_SAD},
    {CAPI_SUBTYPE_DIAG_ASG,     CAPI_SUBTYPE_DIAG_ASG},
};
int numRanges = sizeof(ranges) / sizeof(*ranges);

for( int rangeIdx = 0; rangeIdx < numRanges; ++rangeIdx )
{
    for( int enumValue = ranges[rangeIdx].start; enumValue <= ranges[rangeIdx].end; ++enumValue )
    {
        processEnumValue( enumValue );
    }
}

Or something along those lines.