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

void printArea(double coord[]);

int main()
{

    cout << "Enter the coordinates of six points: \n";
    double coord[12];
    cin >> coord[12];


    cout << "The total area is ";
    printArea(coord);

    return 0;
}


    void printArea(double coord[])
    {
        double D[9];

        D[0] = sqrt(pow(coord[0] - coord[2], 2) + pow(coord[1] - coord[3], 2));
        D[1] = sqrt(pow(coord[2] - coord[4], 2) + pow(coord[3] - coord[5], 2));
        D[2] = sqrt(pow(coord[0] - coord[4], 2) + pow(coord[1] - coord[5], 2));
        D[3] = sqrt(pow(coord[4] - coord[6], 2) + pow(coord[5] - coord[7], 2));
        D[4] = sqrt(pow(coord[0] - coord[6], 2) + pow(coord[1] - coord[7], 2));
        D[5] = sqrt(pow(coord[6] - coord[8], 2) + pow(coord[7] - coord[9], 2));
        D[6] = sqrt(pow(coord[0] - coord[8], 2) + pow(coord[1] - coord[9], 2));
        D[7] = sqrt(pow(coord[8] - coord[10], 2) + pow(coord[9] - coord[11], 2));
        D[8] = sqrt(pow(coord[0] - coord[10], 2) + pow(coord[1] - coord[11], 2));
/* Can you figure out a way to do this in a loop? */

        double S[4];
        S[0] = (D[0] + D[1] + D[2]) / 2;
        S[1] = (D[2] + D[3] + D[4]) / 2;
        S[2] = (D[4] + D[5] + D[6]) / 2;
        S[3] = (D[6] + D[7] + D[8]) / 2;
/* Can you figure out a way to do this in a loop? */

        double A[4];
        A[0] = sqrt(S[0] * (S[0] - D[0]) * (S[0] - D[1]) * (S[0] - D[2]));
        A[1] = sqrt(S[1] * (S[1] - D[2]) * (S[1] - D[3]) * (S[1] - D[4]));
        A[2] = sqrt(S[2] * (S[2] - D[4]) * (S[2] - D[5]) * (S[2] - D[6]));
        A[3] = sqrt(S[3] * (S[3] - D[6]) * (S[3] - D[7]) * (S[3] - D[8]));
/* Can you figure out a way to do this in a loop? */

        double TotalArea = 0;
        for (int i = 0; i < 4; i++)
        {
            TotalArea += A[i];
        }
        cout << TotalArea << endl;

    }