Re: enums and switch vs function calls

Em 4/5/2025 7:29 AM, Richard Harnden escreveu:

If I have:
 enum colour {RED, GREEN, BLUE}
 int colour_to_hex(enum colour colour)
{
     switch (colour)
     {
         RED: return 0xff0000;
         GREEN: return 0x00ff00;
         // BLUE: return 0x0000ff;
     }
      ...
}
 ... then the compiler will warn me that I've missed a case in the switch statement.  Which is good and very helpful.
 But if I do:
 int hex = colour_to_hex(10);
 ... then the compiler doesn't complain that 10 is not in the enum.
 Why? Surely the compiler can tell.

Sometimes enums are used as bit set.
f(BIT1 | BIT2)
this situation would generate a lot of warning because BIT1|BIT2 is not part of the enum, just BIT1 and BIT2 separately.
One way that this could be fixed is adding an attribute
[[bitset]]
enum E{ BIT1 = 2, BIT2 = 4};
Then the compiler would not generate a warning in this case.