std :: make_pair的用途 [英] Purpose of std::make_pair

问题描述

std :: make_pair ？的目的是什么？

为什么不是 std :: pair< int，char>（0，'a'）？

两种方法有什么区别？ / p>

解决方案

不同之处在于 std :: pair 两个元素的类型，而 std :: make_pair 将创建一个与传递给它的元素的类型，而不需要告诉它。

从 http://www.cplusplus.com/reference/std/utility/make_pair/

  pair< int，int>一; 
 pair< int，int>二; 
 
 one = make_pair（10,20）; 
 two = make_pair（10.5，'A'）; // ok：implicit conversion from pair< double，char> 
  

除了隐式转换加成之外，如果你没有使用make_pair， do

  one = pair< int，int>（10,20）
  / pre> 
 
 
每次分配给一个，这将是烦人的时间... 
 
What is the purpose of std::make_pair?

Why not just do std::pair<int, char>(0, 'a')?

Is there any difference between the two methods?
解决方案
The difference is that with std::pair you need to specify the types of both elements, whereas std::make_pair will create a pair with the type of the elements that are passed to it, without you needing to tell it. That's what I could gather from various docs anyways.

See this example from http://www.cplusplus.com/reference/std/utility/make_pair/
pair <int,int> one;
pair <int,int> two;

one = make_pair (10,20);
two = make_pair (10.5,'A'); // ok: implicit conversion from pair<double,char>
Aside from the implicit conversion bonus of it, if you didn't use make_pair you'd have to do
one = pair<int,int>(10,20)
every time you assigned to one, which would be annoying over time...

                        
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