如何将std :: endl传递给函数并使用它? [英] How pass std::endl to a function and use it?

问题描述

我想弄清楚如何将像std::endl这样的操纵器传递给函数，然后在函数中使用传入的操纵器.我可以这样声明函数:

I want to figure out how to pass a manipulator like std::endl to a function and then use the passed-in manipulator in the function. I can declare the function like this:

void f(std::ostream&(*pManip)(std::ostream&));

我可以这样称呼它:

f(std::endl);

没关系.我的问题是弄清楚如何在f中使用操纵器.这不起作用:

That's all fine. My problem is figuring out how to use the manipulator inside f. This doesn't work:

void f(std::ostream&(*pManip)(std::ostream&))
{
  std::cout << (*pManip)(std::cout);            // error
}

无论编译器如何，错误消息都归结为编译器无法确定要调用哪个operator<<.我需要在f内部进行哪些修复才能编译我的代码?

Regardless of compiler, the error message boils down to the compiler not being able to figure out which operator<< to call. What do I need to fix inside f to get my code to compile?

推荐答案

void f(std::ostream&(*pManip)(std::ostream&))
{
  std::cout << "before endl" << (*pManip) << "after endl"; 
}

或

void f(std::ostream&(*pManip)(std::ostream&))
{
  std::cout << "before endl";
  (*pManip)(std::cout);
  std::cout << "after endl"; 
}

这篇关于如何将std :: endl传递给函数并使用它?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！