node（）{}是什么意思？

Question

struct node{
   int key, prior, cnt, val;
   node *l, *r;
   node(){}
   node(int nkey) : key(nkey), prior(rand()), cnt(1), l(0), r(0), val(1){}
};

What does node(){} do ? please explain it, thank you.

Answer 1

它将默认构造函数node()定义为空函数{} 。

Answer 2

What does node(){} do ? please explain it

node(){} looks like treap node. Code node(){} is the syntax for defining the default constructor.

Without default constructor, you can't use node in stl containers like std::array , std::vector etc without extra code so you need the definition for default. In coding competitions, people tend to write the minimal code and use the existing functionality as much as possible sometimes even at the cost of leaking scope etc.