How to check if an enum variable is valid?

Question

I have an enum:

enum myenum{
  typeA,
  typeB,
  typeC
} myenum_t;

Then, a functions is to be called with an enum parameter:

Answer 1

You could use a bitwise enum:

enum myEnum {
    typeA = 1 << 0;
    typeB = 1 << 1;
    typeC = 1 << 2;
}

int myFunction(myEnum arg1)
{
    int checkVal = typeA | typeB | typeC;

    if (checkVal & arg1)
    {
        // do work here;
    }
    else
    {
        printf("invalid argument!");
    }

    return 0;
}

Excuse me, it seems I have read the question wrong.

It appears what you want to do is determine if you have a proper value passed in, not some random invalid option. In that case, the most logical option is this:

if (arg1 < typeA || arg1 > typeC)
    printf("invalid argument");

This is, of course, assuming you don't set manual values for your enum, which, is quite rare unless using bitwise enums.