STL-pair-like triplet class - do I roll my own?

Question

I want to use a triplet class, as similar as possible to std::pair. STL doesn\'t seem to have one. I don\'t want to use something too heavy, like Boost. Is there some useful

Answer 1

I think you need something like this:

template
struct triplet
{
    T first, middle, last;
};

template
triplet make_triplet(const T &m1, const T &m2, const T &m3) 
{
    triplet ans;
    ans.first = m1;
    ans.middle = m2;
    ans.last = m3;
    return ans;
}

Examples of usage:

triplet aaa;
aaa = make_triplet(1.,2.,3.);
cout << aaa.first << " " << aaa.middle << " "  << aaa.last << endl;

triplet bbb = make_triplet(false,true,false);
cout << bbb.first << " " << bbb.middle << " "  << bbb.last << endl;

I'm using this and it is enough for my purposes... If you want different types, though, just do some modifications:

template
struct triplet
{
    T1 first; 
    T2 middle;
    T3 last;
};

template
triplet make_triplet(const T1 &m1, const T2 &m2, const T3 &m3) 
{
    triplet ans;
    ans.first = m1;
    ans.middle = m2;
    ans.last = m3;
    return ans;
}

And the usage will be very similar:

triplet ccc;
ccc = make_triplet(false,"AB",3.1415);
ccc.middle = "PI";
cout << ccc.first << " " << ccc.middle << " "  << ccc.last << endl;