C++ Using an int to set an enum from a list

Question

I am using a header file for character class in a game (doing it as a side project for experience). I have it working but it just feels like I'm doing this the long way. I ask for an 'int' to set the character class then set it based on the enum position using a switch statement. Is there a clearer, shorter way to do this operation? Am I doing anything here that would be considered bad practice?

class Character_Class { public: enum classofnpc { CLERIC, FIGHTER, ROGUE, WIZARD, BARBARIAN, DRUID, PALADIN, SORCERER, BARD, MONK, RANGER, WARLOCK }; Character_Class(const int& a, const int& b){ switch (a) { case 0 : a_class = CLERIC; break; case 1 : a_class = FIGHTER; break; case 2 : a_class = ROGUE; break; case 3 : a_class = WIZARD; break; case 4 : a_class = BARBARIAN; break; case 5 : a_class = DRUID; break; case 6 : a_class = PALADIN; break; case 7 : a_class = SORCERER; break; case 8 : a_class = BARD; break; case 9 : a_class = MONK; break; case 10 : a_class = RANGER; break; case 11 : a_class = WARLOCK; break; } lvl = b; } private: classofnpc a_class; int lvl; };

a_class = a; seems clearer. enums by default start from 0 and increse by one. — zch
– zch, Commented May 6, 2015 at 17:58
@zch Yes, but only with additional check - otherwise it is not safe. int can yields value, that is beyond scope of this enumeration. — Mateusz Grzejek
– Mateusz Grzejek, Commented May 6, 2015 at 18:02
As an aside, I'd recommend only passing large classes by const reference, for primitives it is not necessary, in fact it is often slightly less efficient, you should just pass them by value. — Cory Kramer
– Cory Kramer, Commented May 6, 2015 at 18:30

Cory Kramer · Accepted Answer · 2015-05-06 17:56:15Z

Your constructor could just be

Character_Class(const classofnpc& a, const int& b) : a_class { a }, lvl { b } { }

Since the enum is exposed publicly, you don't need the switch statement. You could instantiate an instance of this class like so

Character_Class foo{ Character_Class::ROGUE, 12 };

Mateusz Grzejek · Accepted Answer · 2015-05-06 17:57:17Z

Is there a clearer, shorter way to do this operation?

Yes.

1. Add sentinel value:

enum classofnpc { CLERIC, //cut... WARLOCK, CLS_LIMIT = WARLOCK //set sentinel to largest value };

2. Check and cast:

Character_Class(const int& a, const int& b) { if(a > CLS_LIMIT) //report error, wrong value passed else a_class = static_cast<classofnpc>(a); lvl = b; }

This is a perfect solution if you want to use numerical values for some reason (user input?). However, if you can, the most type-safe way would be to construct your object using classofnpc as first parameter in constructor (instead of plain int).

a_class = static_cast<classofnpc>(a); Works great for what I'm doing. I already have a check to make sure the int 'a' is within bounds when asking for the input in another function. Thanks for the Answer.

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