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我想寫一個迭代器類,它在解除引用時返回一個getter函數返回值。代碼工作正常,我唯一的問題是我想只使用一個模板參數而不是3來編寫member_ptr_functor,因爲我應該能夠推導出參數的類型並從成員函數類型返回值。我認爲有問題的是參數類型,我嘗試使用boost :: remove_ptr &,但我無法編譯它。迭代指針向量的獲取者
#include <iostream>
#include <vector>
#include <boost/iterator/transform_iterator.hpp>
#include <boost/iterator/indirect_iterator.hpp>
using namespace boost;
using namespace std;
class CTest
{
private:
int m_x;
public:
CTest(int x) : m_x(x)
{
}
const int& GetX() const
{
return m_x;
}
};
template<typename MemFunType, typename ArgumentType, typename ResultType>
class member_ptr_functor : public unary_function<ArgumentType, ResultType>
{
private:
MemFunType m_MemFun;
public:
typedef ArgumentType argument_type;
typedef ResultType result_type;
member_ptr_functor(MemFunType MemFun) : m_MemFun(MemFun)
{
}
result_type operator() (argument_type arg) const
{
return m_MemFun(&arg);
}
};
template<typename MemFunType, typename ArgumentType, typename ResultType>
member_ptr_functor<MemFunType, ArgumentType, ResultType> make_member_ptr_functor(MemFunType MemFun)
{
return member_ptr_functor<MemFunType, ArgumentType, ResultType>(MemFun);
}
class CPrintFunctor : public unary_function<int, void>
{
public:
void operator() (const int n) const
{
cout << n << endl;
}
};
int main()
{
typedef vector<CTest> Container_t;
Container_t v;
v.push_back(CTest(1));
CPrintFunctor PF;
Container_t::const_iterator itStart = v.begin();
Container_t::const_iterator itEnd = v.end();
typedef member_ptr_functor<const_mem_fun_t<const int&, CTest> , CTest, const int&> member_ptr_functor_t;
member_ptr_functor_t MemberPtrFunctor = member_ptr_functor_t(mem_fun(&CTest::GetX));
typedef transform_iterator<member_ptr_functor_t, Container_t::const_iterator, const int&, const int> transform_iterator_t;
transform_iterator_t itTransformStart = make_transform_iterator(itStart, MemberPtrFunctor);
transform_iterator_t itTransformEnd = make_transform_iterator(itEnd, MemberPtrFunctor);
for_each(itTransformStart, itTransformEnd, PF);
return 0;
}
Hagai。
感謝您的回答。 我不熟悉boost.range,它可能是一個很好的長期解決方案。然而,我提供的代碼僅僅是一個例子,我實際上需要我的代碼中的其他東西的迭代器。 – barisdad 2010-08-02 05:42:12