#include <iostream>
#include <cstdlib>
#include <cmath>
#include <cctype>
using namespace std;

struct POINT {
	double x;
	double y;
};

struct POINT g_coord(void);
struct POINT m_point(struct POINT a, struct POINT b);
double d_apart(struct POINT a, struct POINT b);
void p_results(struct POINT a, struct POINT b);
void p_point(struct POINT z);
void p_welcome(void);
void p_end(void);

int main(void) {
	POINT p_one, p_two;
	char garbage[21];
	bool repeat = true;
	p_welcome();
	while(repeat) {
		cout << "Where is your first point? ";
		p_one = g_coord();
		cout << "Where is your second point? ";
		p_two = g_coord();
		cout << endl << "Thank you!!  Calculating...  Done." << endl << endl;
		p_results(p_one, p_two);
		cout << "Would you like to keep going? (Y/N) ";
		cin.getline(garbage, 20);
		if((garbage[0] == 'n') || (garbage[0] == 'N')) {
			repeat = false;
		}
	}
	p_end();
	system("pause");
	return 0;
}

struct POINT g_coord(void) {
	POINT z;
	char coord[256], *end;
	bool digit = false;
	cin.getline(coord, 256);
	if(coord[0] == '(') {
		z.x = strtod(&(coord[1]), &end);
	}
	else {
		z.x = strtod(coord, &end);
	}
	int length = (int)strlen(coord);
	for(int i = 0; i < length; i++) {
		if((*(end + i) == '-') || isdigit((*(end + i)))) {
			z.y = strtod(end + i, &end);
			i = length + 1;
		}
	}

	return z;
}

double d_apart(struct POINT a, struct POINT b) {
	return sqrt(pow((b.x - a.x), 2) + pow((b.y - a.y), 2));
}

struct POINT m_point(struct POINT a, struct POINT b) {
	POINT z;
	z.x = ((a.x + b.x)/2);
	z.y = ((a.y + b.y)/2);
	return z;
}

void p_point(struct POINT a) {
	cout << "(" << a.x << ", " << a.y << ")";
}

void p_welcome(void) {
	cout << "Welcome to the 2D Point Program!!!" << endl << endl;
}

void p_end(void) {
	cout << endl << "Thank you for using the 2PP!!" << endl;
}

void p_results(struct POINT a, struct POINT b) {
	POINT p_one = a;
	POINT p_two = b;
	p_point(p_one); cout << " is " << d_apart(p_one, p_two) << " units away from " << endl;
	p_point(p_two); cout << "." << endl;
	cout << "The midpoint of the line segment from "; p_point(p_one); cout << " to " << endl;
	p_point(p_two); cout << " is "; p_point(m_point(p_one, p_two)); cout << "." << endl << endl;
}