保罗万象的对象——Variant

对一个对象设置其可容纳的多种类型

通过类型对对象进行Set和Get，类型之间互不影响，一个类型只能又一个值

variant.h

/* * variant.h * * Created on: 2012-3-9 * Author: vivence*/#ifndef VARIANT_H_#define VARIANT_H_namespace ghost{template<typename... Tn>class Variant;template<>class Variant<>{};template<typename T, typename... Tn>const T& GetVariant(const Variant<T, Tn...>& t);template<typename T, typename... Tn>T& GetVariant(Variant<T, Tn...>& t);template<typename T, typename... Tn>class Variant<T, Tn...> : public Variant<Tn...>{ T v_;public:const T& GetValue() const{return v_;} T& GetValue(){return v_;} template<typename TT>const TT& Get() const{return GetVariant<TT>(*this);} template<typename TT> TT& Get(){return GetVariant<TT>(*this);} template<typename TT>void Set(const TT& t){Variant<Tn...>::Set(t);}void Set(const T& t){v_ = t;}};template<typename T, typename... Tn>const T& GetVariant(const Variant<T, Tn...>& t){return t.GetValue();}template<typename T, typename... Tn>T& GetVariant(Variant<T, Tn...>& t){return t.GetValue();}} // namespace ghost#endif /* VARIANT_H_ */

 

test.cpp

/* * test.cpp * * Created on: 2012-3-9 * Author: vivence*/#include "variant.h"#include <iostream>#include <iomanip>int main(){ ghost::Variant<int, bool, char> test; test.Set(1); test.Set(false); test.Set('a'); test.Set('b'); std::cout<<test.Get<int>()<<std::endl; std::cout<<std::boolalpha<<test.Get<bool>()<<std::endl; std::cout<<test.Get<char>()<<std::endl;return 0;}

转载于:https://www.cnblogs.com/EvilGhost/archive/2012/03/09/variant.html

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