How to have a set of structs in C++

Question

I have a struct which has a unique key. I want to insert instances of these structs into a set. I know that to do this the < operator has to be overloaded so that set can mak

Answer 1

You can overload the operator < inside the class also as,

struct foo 
{
  int key;
  bool operator < (const foo &other) const { return key < other.key; }
};

In your question, if you want to use set<foo> bar; as declaration then, you should insert value as,

bar.insert(*test);

But that won't be a good idea, as you are making redundant copy.