How to map a bool to a 3d point struct with std::map?

Question

How do I use the following struct:

struct point 
{
    int x;
    int y;
    int z;
};

as a key for std::map

Answer 1

Of course, boost::tuple would make this utterly unnecessary.

Update Adding the all-inclusive have-your-cake-and-eat-it-too no-drawback solution here. IMHO it rocks!

#include 

struct point 
{
    int x, y, z;
    point(int x, int y, int z) : x(x), y(y), z(z) {}
    bool operator<(const point& rhs) const 
    {
        return boost::tie(x, y, z) < boost::tie(rhs.x, rhs.y, rhs.z);
    }
};

Here is the kicker: it all optimizes away. Compile:

int main()
{
    point a(1,2,3), b(3,2,1);
    bool lt = a

With g++ -O2 yields the following in assembly.

main:
.LFB1132:
        pushl   %ebp
        xorl    %eax, %eax
        movl    %esp, %ebp
        popl    %ebp
        ret
.LFE1132:

The compiler was able to optimize the whole of this program to ... return 0 effectively. That is pretty neat.

---

Here goes the simple answer:

struct point 
{
    point(int x, int y, int z) 
        : x(x), y(y), z(z) {}
    int x;
    int y;
    int z;
    bool operator<(const point& rhs) const 
    {
        if (x

Also, I would consider looking for a redefinition of my struct that will allow using std::lexicographical_compare

#include 

// ...
bool operator<(const point& rhs) const 
{
    return std::lexicographical_compare(&xyz, &xyz+3, &rhs.xyz, &rhs.xyz+3);
}