CppTemplateClassExample2.md

 

 

 

 

 

(C++) TemplateClassExample2

 

 

Template class example 2: class that must be specialized; compile-time polymorphism is a template class example.

 

• Download the Qt Creator project 'CppTemplateClassExample2' (zip)

Technical facts

 

Operating system(s) or programming environment(s)

• Lubuntu 15.04 (vivid)

IDE(s):

• Qt Creator 3.1.1

Project type:

• Console application

C++ standard:

• C++98

Compiler(s):

• G++ 4.9.2

Libraries used:

• STL: GNU ISO C++ Library, version 4.9.2

 

 

 

 

 

Qt project file: ./CppTemplateClassExample2/CppTemplateClassExample2.pro

 

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include(../../ConsoleApplication.pri) SOURCES += main.cpp

 

 

 

 

 

./CppTemplateClassExample2/main.cpp

 

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#include <iostream> ///Template class template <class T> struct MyClass {   MyClass(const T& x); }; ///Template class specifialized for int, definition in declaration template <> struct MyClass<int> {   MyClass(const int& x)   {     std::cout << "int: " << x << '\n';   } }; ///Template class specifialized for int, definition seperate after declaration template <> struct MyClass<double> {   MyClass(const double& x); }; MyClass<double>::MyClass(const double& x) {   std::cout << "double: " << x << '\n'; } int main() {   const MyClass<int> m(123);   const MyClass<double> n(3.14);   //Create a MyClass<bool> fails (correctly) with:   //undefined reference to 'MyClass<bool>::MyClass(bool const&)'   //const MyClass<bool> q(true); }