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AdamElKaroui
AdamElKaroui

Reputation: 81

template with enum specialization

I have a template which takes as specialization an enum class (note the different initializations of enum), and I would like to be able to compare two different enums

enum choiceA {One, Two, Three};
typedef enum  {Four, Five, Six} choiceB;

template<typename S>
void f(S choice, int& x)
{
if (choice == One || choice == Four) { x = SomeWhateverIntegerValue;}
else if(choice = Five) {x = AnOtherWhateverIntegerValue;}
else {x = OtherIntegerValue;}
}

so that

int x = 0;
f<choiceA>(One, x);

works as intended.

Upvotes: 0

Views: 57

Answers (1)

bolov
bolov

Reputation: 75688

The fact that you have two enum types for the same enumeration is odd. I would fix that design first.

Anyway to strictly answer your question you don't need templates here. A simple overload would suffice:


void f(choiceA choice, int& x)
{
    if (choice == One)
    {
        x = SomeWhateverIntegerValue;
    }
    else
    {
        x = OtherIntegerValue;
    }
}

void f(choiceB choice, int& x)
{
    if (choice == Four)
    {
        x = SomeWhateverIntegerValue;
    } else if(choice == Five)
    {
        x = AnOtherWhateverIntegerValue;
    }
    else
    {
        x = OtherIntegerValue;
    }
}

As a side note avoid the C style typedef enum/class { ... } Name;.

Also take care if(choice = Five) you have a dangerous typo. It should be ==. Enable compiler warnings, most modern compilers warn about this.

Upvotes: 3

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