istream>> ostream<<带有*指针的运算符重载 [英] istream >> ostream << Operator Overloading with * Pointer

问题描述

我如何重载>>和<<运算符是否正在处理指针?

How would I overload the >> and << operators if they are dealing with pointers?

标题中:

friend std::istream& operator >>( std::istream& ins, Classname* & e);
friend std::ostream& operator <<( std::ostream& outs, const Classname * e);

在cpp中:

std::ostream& operator <<( std::ostream& outs, const Classname * e)
{   // what do I do here?
return outs;
}
std::istream& operator >>( std::istream& ins, Classname* & e){
// what do I do here?
    return ins;
}

推荐答案

这取决于类Classname中的内容.例如，如果您有:

It depends on what is in the class Classname. If for example you have:

class Classname {
//...
private:
  int a;
};

..那么您可以这样做:

.. then you might do:

std::ostream& operator <<( std::ostream& outs, const Classname * e)
{  
  outs << e->a;
  return outs;
}
std::istream& operator >>( std::istream& ins, Classname* & e){
    ins >> e->a;
    return ins;
}

<<和>>运算符在理想情况下应该相互镜像-因此，例如，您可以利用它们对您的实例进行序列化和反序列化.

The idea being that the << and >> operators ideally should mirror each other - so for example you can make use of them for serializing and deserializing your instances.

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