c++ - Can a class have a templated constructor without arguments? -



c++ - Can a class have a templated constructor without arguments? -

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derive template constuctor of template base of operations class 3 answers

i have want have class looks like:

template <typename t> class foo { public: template <typename s> foo() { //... } };

but cannot figure out how phone call constructor. obviously, can create work giving foo() argument of type s can done without arguments?

--ron

you can't pass template arguments explicitly constructor template. constructors don't have names.

[ note: because explicit template argument list follows function template name, , because conversion fellow member function templates , constructor fellow member function templates called without using function name, there no way provide explicit template argument list these function templates. — end note ]

although can name constructor using syntax foo<int>::foo, can used in ways aren't of involvement here:

in lookup in constructor acceptable lookup result , nested-name-specifier nominates class c: — if name specified after nested-name-specifier, when looked in c, injected-class-name of c (clause 9), or — […] the name instead considered name constructor of class c. […] such constructor name shall used in declarator-id of declaration names constructor or in using-declaration.

c++ templates

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