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

In c++11 we can use a lambda expression, I used this way which is similar to what @Oliver was given.

#include 
#include 
#include 

struct Blah
{
    int x;
};



int main(){

    auto cmp_blah = [](Blah lhs, Blah rhs) { return lhs.x < rhs.x;};

    std::set my_set(cmp_blah);

    Blah b1 = {2};
    Blah b2 = {2};
    Blah b3 = {3};

    my_set.insert(b1);
    my_set.insert(b2);
    my_set.insert(b3);

    for(auto const& bi : my_set){
        std::cout<< bi.x << std::endl;
    }

}

demo