检查ostream对象是cout还是stream，c ++ [英] Check if ostream object is cout or ofstream, c++

问题描述

在C ++中有一种方法来检查 ostream 对象是 cout 还是 ofstream object？

Is there a way in C++ to check if an ostream object is cout or a ofstream object?

如下：

ostream& output(ostream& out)
{
    if (out == cout)
        return out;
    else
    {
        out << "something different because its not going to the console" << endl;
        return out;
    }
}

我想这样做的原因是想要重载<< 运算符根据使用的流类型做两个不同的事情。

The reason I want to do this, is that I want to overload the << operator to do two different things depending on what type of stream it is used with.

是否可以每次使用不同类型的流重载< 运算符两次？

Is it possible to just overload the << operator twice each time with a different type of stream?

更新以反映意图更好。

推荐答案

可以通过检查流的身份： if（& out ==& cout）... 。

It's possible by checking the stream's 'identity': if ( &out == &cout ) ....

但是，我对此测试的用途有疑问。如果你的函数可以处理任何输出流，为什么要考虑使用什么流？

However, I'm in doubt on the usefullness of this test. If your function can handle any output stream, why bother about what stream it is using?

这篇关于检查ostream对象是cout还是stream，c ++的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！