// ic210 sec 4002
//6 nov 2009
// read, sort, and print
//an array of "points" by "magnitude"
// each "point" is an array with 3 elements
// "magnitude" of (a,b,c) is a^2+b^2+c^2
#include <iostream>
#include <fstream>
#include <cmath>
#include <string>

using namespace std;


int maxIndex(double* *array, int size);
void selectionSort(double* *arrayIn, int sizeIn);
void swap(double*& a, double*& b);
int search(double* value, double** arrayIn, int size);
bool isBefore(double*, double*);

//point functions
double* readPoint(istream &in);
void  writePoint(double *point, ostream &out);
double magnitude(double *point);

int main()
{

	
	ifstream fin("class28_data.txt");
	if (!fin)
	{
		cout << "Error" << endl;
		exit(1);
	}

	// create array and initialize with values
	int size ;
	fin >> size;
	double** array = new double*[size];

	
	for (int i = 0; i < size; i++)
	{
		array[i] = readPoint(fin);	
	}

	// sort the array
	selectionSort(array, size);

	// display the array
	for (int j = 0; j < size; j++)
	{
		writePoint(array[j],cout);
		cout << endl;
	}

	return 0;
}


// Returns the index of the maximum element in the array 
int maxIndex(double* *array, int size)
{

	int maxIndex = 0;
	//int maxValue = array[0];

	for (int i=1; i < size; i++)
	{
		if (isBefore(array[maxIndex],array[i])) 
		{
			maxIndex = i;
			//maxValue = array[i];
		}
	}
	return maxIndex;

}

// What does this function do?
//sorting the array
//selection sort
void selectionSort(double* *arrayIn, int sizeIn)
{

	for(int size = sizeIn; size > 1; size--)
	{
		//int k = maxIndex(arrayIn,size);

		swap(arrayIn[maxIndex(arrayIn,size)], arrayIn[size-1]);
		//int temp = arrayIn[size-1];
		//arrayIn[size-1] = arrayIn[k];
		//arrayIn[k] = temp;
	}
}


void swap(double*& a, double*& b)
{
	double* temp = a;
	a = b;
	b = temp;
}


bool isBefore(double* a, double* b)
{
	return magnitude(a) < magnitude(b);
	
}


// Read in a point (x,y,z) coordinates -- return as array
double* readPoint(istream &in) {
    double *point = new double[3];
    in >> point[0];
    in >> point[1];
    in >> point[2];
    return point;
}

// Write the point to cout
void    writePoint(double *point, ostream &out) {
    out << point[0] << "," << point[1] << "," << point[2];
}

// Calculates magnitude of given array of 3 doubles (x,y,z)
double magnitude(double *point) {
    double sum = point[0]*point[0] + point[1]*point[1] + point[2]*point[2];
    return sqrt(sum);
}