треугольник доделать

#include <iostream>
#include <cmath>
#include <iomanip>

using namespace std;

#define PI 3.14159265

class vector1
{
  public:
  double x1, y1, x2, y2;
  double length;

 vector1()
 {
   length = sqrt((x2-x1)*(x2-x1) + (y2-y1)*(y2-y1));
 }
};

struct vershina
{
  double x, y;
};

vector1 sozdanie(vershina one, vershina two)
{
  vector1 a;
  a.x1 = one.x;
  a.y1 = one.y;
  a.x2 = two.x;
  a.y2 = two.y;
  return a;
}

double ygol (vector1 one, vector1 two, vector1 three)
{
 double znach;
 znach = (one.length*one.length + two.length*two.length - three.length*three.length)/2*one.length*two.length;
 return znach;
}

int main ()
{
  int result = 0;
  vershina A, B, C;
  cin >> A.x >> A.y >> B.x >> B.y >> C.x >> C.y;

  vector1 *arr = new vector1[3];

    arr[0] = sozdanie(A, B);
    arr[1] = sozdanie(B, C);
    arr[2] = sozdanie(A, C);

  double znach = arr[0].length;

  for (int i = 0; i<3; i++)
    if (znach < arr[i].length)
     {
       znach = arr[i].length;
       result = i;
     }

  double itog;

  if (result == 0)
   itog = ygol(arr[1], arr[2], arr[0]);
  else if (result == 1)
   itog = ygol(arr[0], arr[2], arr[1]);
  else itog = ygol(arr[1], arr[0], arr[2]);

  znach = acos(itog)*180.0/PI;
  cout.precision(6);
  cout << fixed << znach;
}