How to sort a multidimensional vector of floats?

Question

So, I have a set of points in 3D, and I would like to store them in a 3 dimensional vector. Then I need sort that vector, giving priority first to the X dimention, then Y, then

Answer 1

You can use the std::sort() to easily sort according to your specific conditions by making your own comparator function.

Assuming you have stored a single 3D point in a struct point, and the points in a std::vector (A std::tuple might be more useful.), try out this code.

Example:

#include 
#include 
using namespace std;
struct point
{
     float x, y, z;
}
bool mySort(const point& a, const point& b)
{
    //A naive comparison to help you understand better.
    //You could always use std::tie for lexicographical comparison.
    if (a.x == b.x)
    {
        if (a.y == b.y)
            return a.z < b.z;
        else
            return a.y < b.y;
    }
    else
        return a.x < b.x;
}
int main()
{
    vector graph;
    //push_back() all your points into the graph.
    //mySort() is a custom comparator function.
    sort(graph.begin(),graph.end(),mySort); 
}