(C++) HostClassExample3

 

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: ./CppHostClassExample3/CppHostClassExample3.pro

 

---

include(../../ConsoleApplication.pri) #Or use the code below # QT += core # QT += gui # greaterThan(QT_MAJOR_VERSION, 4): QT += widgets # CONFIG   += console # CONFIG   -= app_bundle # TEMPLATE = app # CONFIG(release, debug|release) { #   DEFINES += NDEBUG NTRACE_BILDERBIKKEL # } # QMAKE_CXXFLAGS += -std=c++11 -Wall -Wextra -Weffc++ # unix { #   QMAKE_CXXFLAGS += -Werror # } SOURCES += main.cpp

 

 

 

 

 

./CppHostClassExample3/main.cpp

 

---

#include <cassert> #include <fstream> #include <iostream> #include <string> #include <vector> template <class T> struct CheckPolicyNotEmpty {   void Check(const T& s)   {     assert(!s.empty() && "Object must not be empty");   } protected:   ~CheckPolicyNotEmpty()   {     // The destructor of a policy class should be protected and non-virtual:     // * Herb Sutter, Andrei Alexandrescu. C++ coding standards: 101 rules,     //   guidelines, and best practices. ISBN: 0-32-111358-6. Item 50: 'Make     //   base class destructors public and virtual, or protected and nonvirtual'     // * Andrei Alexandrescu. Modern C++ Design. 2001. ISBN: 0201704315.     //   Page 13. Section 1.7: 'The lightweight, effective solution that     //   policies should use is to define a nonvirtual protected destructor'   } }; template <class T> struct CheckPolicyNotNull {   void Check(const T& p)   {     assert(p && "Pointer must not be null");   } protected:   ~CheckPolicyNotNull()   {     // The destructor of a policy class should be protected and non-virtual:     // * Herb Sutter, Andrei Alexandrescu. C++ coding standards: 101 rules,     //   guidelines, and best practices. ISBN: 0-32-111358-6. Item 50: 'Make     //   base class destructors public and virtual, or protected and nonvirtual'     // * Andrei Alexandrescu. Modern C++ Design. 2001. ISBN: 0201704315.     //   Page 13. Section 1.7: 'The lightweight, effective solution that     //   policies should use is to define a nonvirtual protected destructor'   } }; ///Manager keeps a std::vector in a valid state template <class T, typename CheckPolicy> struct Manager : public CheckPolicy {   Manager(const std::vector<T>& v) : m_v(v) { CheckAll(); }   private:   std::vector<T> m_v;   void CheckAll()   {     for (const T& t: m_v) this->Check(t);   } }; int main() {   {     const std::vector<int *> v       = { new int, new int, new int };     //const std::vector<int *> v     //  = { new int, new int, nullptr }; //nullptr will be detected     const Manager<int *, CheckPolicyNotNull<int *> > pointers( v );     for (int * p: v) delete p;   }   {     const Manager<std::string, CheckPolicyNotEmpty<std::string> > strings(       { "1", "12", "123" } );     //const Manager<std::string, CheckPolicyNotEmpty<std::string> > strings(     //  { "1", "12", "" } ); //empty std::string will be detected   } }