std :: initializer_list<>和参考参数 [英] std::initializer_list<> and a Reference Parameter
问题描述
我刚开始使用初始化列表,我想知道他们是否工作类似于其他stl容器。我的意思是他们复制值?我想做的是一个简单的min()函数像这样:
template< class T&夯; minArgs(const std :: initializer_list< T&>& Arguments)
{
const T * Smallest = Arguments.begin
for(const T * I = begin(Arguments); I!= end(Arguments); ++ I)
{
if(* I <* Smallest)
}
return * Smallest;但是当我调用函数时,我从GCC得到这个:
错误:'const'限定符不能应用于'int&'
我一直在玩这个,似乎initializer_lists可能不会做我想要的;我想要的函数除了非POD参数,以及。
解决方案
当我尝试时,我会收到这些错误。但是,当我摆脱了对参考文献的无谓使用时,一切正常。
std :: initializer_list
存储值,而不是引用。你应该用一个 const std :: initializer_list< T> &
,而不是 const std :: initializer_list< T&> &
。
我所要做的就是写一个函数,通过引用,并返回对其中最大的引用。
[...]
这是否可能与initializer_lists?
否。 std :: initializer_list
是值,而不是引用。但我没有看到任何理由,你不能采取的价值,而不是通过参考的项目。或者,更重要的是,为什么不使用 std :: min
,它可以接受初始化列表?
I'm new to using initializer lists and I'm wondering if they work similar to other stl containers. By that I mean do they copy values? What I'm trying to do is a simple min() function like this:
template <class T> T& minArgs(const std::initializer_list<T&>& Arguments)
{
const T* Smallest = Arguments.begin();
for (const T* I = begin(Arguments); I != end(Arguments); ++I)
{
if (*I < *Smallest) Smallest = I;
}
return *Smallest;
}
However when I call the function I get this from GCC:
error: 'const' qualifiers cannot be applied to 'int&'
I've been playing around with this and it seems initializer_lists may not do what I want; I want the function to except non-POD arguments as well. Would a va_list be a better alternative?
Thanks!
解决方案 When I try it, I get these errors. Yet, when I get rid of your pointless use of references, it all works.
std::initializer_list
stores values, not references. You should be taking a const std::initializer_list<T> &
, not a const std::initializer_list<T&> &
.
All I'm trying to do is write a function that takes any number of arguments, by reference, and returns a reference to the largest of them.
[...]
Is this possible with initializer_lists?
No. std::initializer_list
is for values, not references. But I see no reason why you couldn't take the items by value instead of by reference. Or, more to the point, why don't you just use std::min
, which can take an initializer list?
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