bool Vector3D::operator< (const Vector3D& other) const
{
for(int k = 0; k < NUM_COORDINATES; ++k)
if(coordinates[k] < other.coordinates[k]) return true;
return false;
}

Vector3D.h

class Vector3D
{
public:

Vector3D();

void set(int arrayIndex,int num);

bool operator< (const Vector3D& other) const;

private:

static const int NUM_COORDINATES = 3;
double coordinates[NUM_COORDINATES];
};



Vector3D.cpp

#include "Vector3D.h"

Vector3D::Vector3D(void){

}


 void Vector3D::set(int arrayIndex,int num){

coordinates[arrayIndex]=num;



}
 bool Vector3D::operator< (const Vector3D& other) const
 {
for(int k = 0; k < NUM_COORDINATES; ++k)
if(coordinates[k] < other.coordinates[k]) return true;
return false;
 }