[英]c++ vector iterator to function template
I'm new to STL. 我是STL的新手。 I'm trying to write a routine taking vector iterators as parameters.
我正在尝试编写一个以矢量迭代器为参数的例程。 Namely, I need to pass vector.begin() and vector.end().
也就是说,我需要传递vector.begin()和vector.end()。 Can't figure why my code is not working:
无法理解我的代码无效的原因:
template<typename T, typename Iter> void VectorQuickSort(Iter itL, Iter itR){
const int nSize = (itR - itL);
if(nSize<2) return;
Iter iBeginning(itL), iEnd(itR);
--itR;
T tPivot = *( itL + (nSize/2) );
while( itL <= itR ){
while( *itL < tPivot ) ++itL;
while( *itR > tPivot ) --itR;
if( itL <= itR ){
std::iter_swap(itL,itR);
++itL;
--itR;
}
}
VectorQuickSort(iBeginning,itR);
VectorQuickSort(itL,iEnd);
}
And in main()
I simply call VectorQuickSort(vInput.begin(),vInput.end());
在
main()
我只需调用VectorQuickSort(vInput.begin(),vInput.end());
. 。 Compiler tells me
error: no instance of function template "VectorQuickSort" matches the argument list
. 编译器告诉我
error: no instance of function template "VectorQuickSort" matches the argument list
。 Any help appreciated :) 任何帮助赞赏:)
EDIT: As a warning for someone potentially trying to use the code above: even if you apply the answer provided, there is still something wrong with the sorting algo itself. 编辑:作为对可能尝试使用上述代码的人的警告:即使您应用了提供的答案,排序算法本身仍然存在问题。 I fail to translate properly working C version into STL style.
我无法正确地将C版本转换为STL样式。
It can't deduce the template parameter T
from those arguments. 它不能从这些参数中推导出模板参数
T
In fact, you don't even need T
. 事实上,你甚至不需要
T
It is redundant because you can work out the type of T
from Iter
- after all, the iterator iterates over elements of type T
. 它是多余的,因为你可以从
Iter
出T
的类型 - 毕竟,迭代器迭代了T
类型的元素。 Change it to just this: 将其更改为:
template<typename Iter>
Then, if you're using C++11, you can change the line that uses T
to automatically deduce the type of tPivot
: 然后,如果您使用的是C ++ 11,则可以更改使用
T
的行来自动推断tPivot
的类型:
auto tPivot = *( itL + (nSize/2) );
If you don't have C++11 support, you can instead use std::iterator_traits
to determine the appropriate type: 如果您没有C ++ 11支持,则可以使用
std::iterator_traits
来确定适当的类型:
typename std::iterator_traits<Iter>::value_type tPivot = *( itL + (nSize/2) );
You can perhaps simplify this with a typedef
: 您可以使用
typedef
简化此操作:
typedef typename std::iterator_traits<Iter>::value_type value_type;
value_type tPivot = *( itL + (nSize/2) );
You need to write VectorQuickSort<int,/*iterator type*/>(vInput.begin(),vInput.end());
您需要编写
VectorQuickSort<int,/*iterator type*/>(vInput.begin(),vInput.end());
or whatever you'd like it to be templated above, notice you mention it's templated over T but the function has no way to deduce where/how T is templated... Either delete T and use auto or tell the function how is T templated 或者你想要它在上面模仿的任何东西,请注意你提到它的模板超过T但是该函数无法推断T的模板在哪里/如何...删除T并使用auto或告诉函数如何模板化
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