C++ 如何遍历 std::list<MyClass *> 并从迭代器获取该类中的方法？
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原文地址: http://stackoverflow.com/questions/1445736/
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How do I iterate through a std::list<MyClass *> and get to the methods in that class from the iterator?
提问by Loren C Fortner
If I have the list,
如果我有名单，
typedef std::list<MyClass *> listMyClass;
How do I iterate through them and get to the methods in that class?
如何遍历它们并访问该类中的方法？
This is what I've tried, but that is not it: (MyClass::PrintMeOut() is a public method)
这是我尝试过的，但事实并非如此：（MyClass::PrintMeOut() 是一个公共方法）
for(
listMyClass::iterator listMyClassIter = listMyClass.begin();
listMyClassIter != listMyClass.end();
listMyClassIter ++)
{
listMyClassIter->PrintMeOut();
}
回答by Phil Miller
Use this method:
使用这个方法：
(*listMyClassIter)->PrintMeOut();
回答by Martin York
for_each and function pointer:
for_each 和函数指针：
std::for_each( listMyClass.begin(),
listMyClass.end(),
std::mem_fun(&MyClass::PrintMeOut)
);
I prefer using the for_each() construct rather than writting my own loop.
It makes it look neat and does all the things I would otherwise need extra code for.
我更喜欢使用 for_each() 构造而不是编写自己的循环。
它使它看起来很整洁，并且可以完成我需要额外代码才能完成的所有事情。
- Only calling end() once rather than each iteration.
- Remembering to use pre increment rather than post increment.
- Needing to work out the actual types of my iterators.
- I am sure there are more but its early in the morning here.
- 只调用 end() 一次而不是每次迭代。
- 记住使用前增量而不是后增量。
- 需要计算出我的迭代器的实际类型。
- 我相信还有更多，但这里是清晨。
回答by Kirill V. Lyadvinsky
typedef std::list<MyClass*> listMyClass;
listMyClass instance; // instance, you shouldn't use type in the following loop
for( listMyClass::iterator listMyClassIter = instance.begin(); // not listMyClass.begin()
listMyClassIter != instance.end(); // not listMyClass.end()
listMyClassIter ++)
{
(*listMyClassIter)->PrintMeOut();
}
回答by Rick
std::for_each in is incredibly well suited for this, some compilers are now picking up lambdas from C++0x which makes this even more intuitive.
std::for_each in 非常适合这一点，一些编译器现在从 C++0x 中提取 lambdas，这使得这更加直观。
typedef std::list<MyClass*> MyClassList;
MyClassList l;
for_each(l.begin(),l.end(),[](MyClass* cur)
{
cur->PrintMeOut();
});
for_each (and the rest of the algorithms) help mask the abstraction between the iterators and types. Also note that now I have this little tiny lambda function (or it could be a functor too) which is more testable, mockable, replacable etc.
for_each（以及其他算法）有助于掩盖迭代器和类型之间的抽象。还要注意，现在我有这个小小的 lambda 函数（或者它也可以是一个函子），它更可测试、可模拟、可替换等。
If I go back to notusing lambdas I can build a stand along method to do this, which is testable:
如果我回到不使用 lambdas 的状态，我可以构建一个独立的方法来做到这一点，这是可测试的：
void PrintMyClass(MyClass* cur)
{
cur->PrintMeOut();
}
and the for_each code now looks like this:
现在 for_each 代码如下所示：
typedef std::list<MyClass*> MyClassList;
MyClassList l;
for_each(l.begin(),l.end(),&PrintMyClass);
