#include <iostream>
#include <fstream>
using namespace std;
struct souradnice {
	double x;
	double y;
};

const int n = 50;
double obsah(double a, double b, double c)
{
	double s = (a + b + c) / 2;
	double S = 0;
	S = sqrt(s*(s - a)*(s - b)*(s - c));
	return S;
}

int main(void)
{
	souradnice bodu[n];
	ifstream vstup("Points.txt");
	for (int i = 0; i < n; i++)
	{
		vstup >> bodu[i].x >> bodu[i].y;
		cout << bodu[i].x << " " << bodu[i].y << endl;
		double Ax = bodu[i].x;
		double Ay = bodu[i].y;
		double Bx = bodu[i].x;	//nevím jak přiřadit ty body  A,B,C - nwm jestli jsem pochopil dobře zadání, protože teď samozřejmě vyjde blbost
		double By = bodu[i].y;
		double Cx = bodu[i].x;
		double Cy = bodu[i].y;
		double a = sqrt((Bx - Cx)*(Bx - Cx) + (By - Cy)*(By - Cy));
		double b = sqrt((Ax - Cx)*(Ax - Cx) + (Ay - Cy)*(Ay - Cy));
		double c = sqrt((Ax - Bx)*(Ax - Bx) + (Ay - By)*(Ay - By));
		double obs = obsah(s, a, b, c);
		cout << obs << endl;
	}
	vstup.close();
	system("pause");
	return 0;