C ++ operator overloading with STL card with user classes

Question

I have doubts about using a stl card in C ++. I know, using a map with custom classes, I need to overload the operator "<" to make the map work. But how can I define it in a meaningful way. For example, I have the following code

#include <iostream>
#include <map>
using namespace std;

struct box{
    int e,s,w;
    box(): e(-1), s(-2), w(-3)
    {}

       bool operator< (const box& lhs) const
       {
           return e < lhs.e;
       }

};

int main() {
    // your code goes here
    map<box, int> hashtable;
    box b;
    hashtable[b] = 1;
    return 0;
}

Here I overloaded the <operator is very trivial. I could overload it also as follows

bool operator< (const box& lhs) const
{
    return w+s+e < lhs.e+lhs.s+lhs.w;
}

And there are other ways. So my question is whether this overloads the <operator, affects the search, removes the access time to the elements on the map. I mean, does this affect the hashing of part of the cards. If so, what is the best way to overload the <statement.

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UPDATE

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bool operator< (const box& lhs) const
{
    return e < lhs.e;
}

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bool operator< (const box& lhs) const
{
    return std::tie(e,w,s) < std::tie(lhs.e,lhs.w,lhs.s);
}

, . . , (1,2,3) (2,1,3).

bool operator< (const box& lhs) const
{
    return e+w+s < lhs.e+lhs.w+lhs.s;
}

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Answer 1

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, std:: tie:

bool operator<(const box& lhs) const
{
    return std::tie(e, s, w) < std::tie(lhs.e, lhs.s, lhs.w);
}

Answer 2

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