func_code_string: #include <bits/stdc++.h>   int main() {     const double eps = 1e-6;     double x[3], y[3];     for (int i = 0; i < 3; ++i) scanf( %lf%lf , &x[i], &y[i]);     x[1] -= x[0];     x[2] -= x[0];     y[1] -= y[0];     y[2] -= y[0];     x[0] = y[0] = 0;     double cx = (y[2] * (x[1] * x[1] + y[1] * y[1]) -                  y[1] * (x[2] * x[2] + y[2] * y[2])) /                 (x[1] * y[2] - x[2] * y[1]) / 2;     double cy = (x[2] * (x[1] * x[1] + y[1] * y[1]) -                  x[1] * (x[2] * x[2] + y[2] * y[2])) /                 (x[2] * y[1] - x[1] * y[2]) / 2;     double dx[3], dy[3];     for (int i = 0; i < 3; ++i) dx[i] = x[i] - cx, dy[i] = y[i] - cy;     double sin_t1 =         (dx[0] * dy[1] - dx[1] * dy[0]) / (dx[0] * dx[0] + dy[0] * dy[0]);     double cos_t1 =         (dx[0] * dx[1] + dy[0] * dy[1]) / (dx[0] * dx[0] + dy[0] * dy[0]);     double sin_t2 =         (dx[0] * dy[2] - dx[2] * dy[0]) / (dx[0] * dx[0] + dy[0] * dy[0]);     double cos_t2 =         (dx[0] * dx[2] + dy[0] * dy[2]) / (dx[0] * dx[0] + dy[0] * dy[0]);     for (int n = 3; n <= 100; ++n) {       for (int i = 1; i < n; ++i) {         if (fabs(sin_t1 - sin(2 * M_PI / n * i)) > eps ||             fabs(cos_t1 - cos(2 * M_PI / n * i)) > eps)           continue;         for (int j = 1; j < n; ++j) {           if (fabs(sin_t2 - sin(2 * M_PI / n * j)) > eps ||               fabs(cos_t2 - cos(2 * M_PI / n * j)) > eps)             continue;           printf( %.9f n ,                  (dx[0] * dx[0] + dy[0] * dy[0]) * sin(2 * M_PI / n) * n / 2);           return 0;         }       }     }     return 0;   }   