templates

Argument list for class template is missing

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First of all, this is how you should provide a definition for member functions of a class template: #include “LinkedArrayList.h” template<typename ItemType> void LinkedArrayList<ItemType>::insert (int index, const ItemType& item) {} template<typename ItemType> ItemType LinkedArrayList<ItemType>::remove (int index) {return ItemType();} template<typename ItemType> int LinkedArrayList<ItemType>::find (const ItemType& item) {return -1;} Secondly, those definitions cannot be put in a … Read more

Why doesn’t the standard consider a template constructor as a copy constructor?

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Let’s put templates aside for a second. If a class doesn’t declare a copy constructor, an implicitly defaulted one is generated. It may be defined as deleted, but it’s defaulted nonetheless. A member template is not a member function. Members are instantiated from it only when needed. So how can a compiler know from the … Read more

Is there a way to do a C++ style compile-time assertion to determine machine’s endianness?

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If you’re using autoconf, you can use the AC_C_BIGENDIAN macro, which is fairly guaranteed to work (setting the WORDS_BIGENDIAN define by default) alternately, you could try something like the following (taken from autoconf) to get a test that will probably be optimized away (GCC, at least, removes the other branch) int is_big_endian() { union { … Read more

Why default argument cannot be specified for an explicit template specialization?

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I think that the rationale behind this error is due to the fact that the default arguments in the function template apply to its specialization as well and you are not allowed to define the default argument more than once in C++. Consider the following: #include <iostream> template<class T> void f(T t=”a”) {} template<> void … Read more

Can we have a function with multiple return types? (in C++11 and above)

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The return type must be determined at compile-time. You might use std::common_type (since C++11): For arithmetic types not subject to promotion, the common type may be viewed as the type of the (possibly mixed-mode) arithmetic expression such as T0() + T1() + … + Tn(). template < typename T, typename X> typename std::common_type<T, X>::type Max_Number … Read more

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