如何在C ++中实现一个生成器？

问题描述：

我想知道如何在C ++中实现一个生成器，如Python。
Python可以使用关键字yield这样做。
但是如何在C ++中做呢？

I want to know how to implement a generator , like Python, in C++? Python can use keyword "yield" to do so. But how to do it in C++?

答

在C ++中我们有'iterators'。一个明确要求一个interator，显式增加和解引用它。

In C++ we have 'iterators'. One explicitly asks for an interator, explicitly increments it and dereferences it.

如果你想要它们与标准库函数一起使用，他们应该主要从 std :: forward_iterator ，并实现一些函数。

If you want them to be used with the standard library functions, they should mostly be derived from std::forward_iterator, and implement a number of it's functions.

另一种方法来模拟一个集合允许一个函数作为一个成员函数的参数，将该函数的所有值馈送（产生）给该函数：

An other way to mimic kindof a generator on a collection is allowing a function as argument to a member function that feeds (yields) all of it's values to that function:

struct MyCollection {
    int values[30];

    template< typename F >  
    void generate( F& yield_function ) const {
       int* end = values+30; // make this better in your own code :)
       for( auto i: values ) yield_function( *i );
    }
};

// usage:
c.generate([](int i){ std::cout << i << std::endl; });

// or pre-C++11:
struct MyFunction { 
    void operator() (int i)const { printf( "%d\n", i); }
};
MyCollection c;
c.generate( MyFunction() );

如何在C ++中实现一个生成器？

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