[英]c++ templated container scanner
here's today's dilemma: 这是今天的两难境地:
suppose I've 假设我已经
class A{
public:
virtual void doit() = 0;
}
then various subclasses of A, all implementing their good doit method. 然后是A的各个子类,都实现了它们的良好doit方法。 Now suppose I want to write a function that takes two iterators (one at the beginning of a sequence, the other at the end).
现在假设我想编写一个带有两个迭代器的函数(一个在序列的开头,另一个在结尾)。 The sequence is a sequence of A subclasses like say
list<A*>
or vector... The function should call all the doit methods while scanning the iterators... How to do this? 该序列是A子类的序列,例如
list<A*>
<A *>或vector ...该函数应在扫描迭代器时调用所有doit方法...如何执行此操作? I've thought of: 我想到了:
template<typename Iterator> void doList(Iterator &begin, Iterator &end) {
for (; begin != end; begin++) {
A *elem = (serializable*) *begin;
elem.doIt();
}
}
but gives weird errors... do you have better ideas or specific information? 但是会产生奇怪的错误...您有更好的主意或特定信息吗? Is it possible to use
list<A>
instead of list<A*>
? 是否有可能使用
list<A>
而不是list<A*>
Why do you think you need the cast? 为什么您认为需要演员表? If it is a collection of A * you should just be able to say:
如果它是A *的集合,您应该可以说:
(*begin)->doIt();
You can use the std::foreach
for that: 您可以使用
std::foreach
来实现:
std::for_each( v.begin(), v.end(), std::mem_fun( &A::doIt ) );
The std::mem_fun
will create an object that calls the given member function for it's operator()
argument. std::mem_fun
将创建一个对象,该对象为其operator()
参数调用给定的成员函数。 The for_each
will call this object for every element within v.begin()
and v.end()
. for_each
将为v.begin()
和v.end()
每个元素调用此对象。
You should provide error messages to get better answers. 您应该提供错误消息以获得更好的答案。
In your code, the first thing that comes to mind is to use 在您的代码中,首先想到的是使用
elem->doIt();
What is the "serializable" type ? 什么是“可序列化”类型?
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