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

The best thing to do is to give foo a constructor:

struct foo
{
    foo(int k) : key(k) { }
    int key;
};

Then to add, rather than...

foo *test = new foo;
test->key = 0;
bar.insert(test);   // BROKEN - need to dereference ala *test
// WARNING: need to delete foo sometime...

...you can simply use:

bar.insert(foo(0));