Question

If I have:

Class MyClass {
public:
    MyClass( /* args */ );
private:
    someType member0;
    someType member1;
    // ...
    someType memberN;
#if defined(FIRST_COMPILE_CONDITION)
    someType condition1Member0;
    someType condition1Member1;
    // ...
    someType condition1MemberN;
#endif
#if defined(SECOND_COMPILE_CONDITION)
    someType condition2Member0;
    someType condition2Member1;
    // ...
    someType condition2MemberN;
#endif
};

for some arbitrary number of compile conditions, is there a clean way to do the equivalent of this (especially for possibly multiple compile conditions), without putting some permanent member last?

MyClass::MyClass( /* args */ ) :
    member0( someValue ),
    member1( someValue ),
    // ...
    memberN( someValue ),
#if defined(FIRST_COMPILE_CONDITION)
    condition1Member0( someValue ),
    condition1Member1( someValue ),
    // ...
    condition1MemberN( someValue ),
#endif
#if defined(SECOND_COMPILE_CONDITION)
    condition2Member0( someValue ),
    condition2Member1( someValue ),
    // ...
    condition2MemberN( someValue ),
#endif
// ...
{
}

As the above will not compile under most conditions due to the trailing comma.

Edit to clarify:

It probably should be noted explicitly that someValue is intended to be a potentially independent, arbitrary value that may or may not depend on constructor arguments in each case used.

Answer 1

You can put the comma before initializers:

MyClass::MyClass() :
     member0( someValue )
    ,member1( someValue )
    // ...
    , memberN( someValue )
#if defined(FIRST_COMPILE_CONDITION)
    ,condition1Member0( someValue )
    ,condition1Member1( someValue )
    // ...
    ,condition1MemberN( someValue )
#endif
// ...
{
}