func_code_string: #include <bits/stdc++.h>   using namespace std;   const double pi = acos(-1.0), eps = 1e-4;   double fgcd(double a, double b) {     return fabs(a) < eps ? b : (fabs(b) < eps ? a : fgcd(b, fmod(a, b)));   }   int main() {     double a, b, c, d, e, f;     cin >> a >> b >> c >> d >> e >> f;     c -= a;     e -= a;     d -= b;     f -= b;     a = (c * c + d * d) / 2;     b = (e * e + f * f) / 2;     double ov = 1.0 / (d * e - c * f);     double A = (d * b - f * a) * ov, B = (e * a - c * b) * ov;     double R = sqrt(A * A + B * B), G1 = asin(sqrt(a * 2) / (R * 2)),            G2 = asin(sqrt(b * 2) / (R * 2)),            G = asin(hypot(c - e, d - f) / (R * 2));     G = fgcd(G1, fgcd(G2, pi));     G = pi / round(pi / G);     A = round(pi / G) * R * R * sin(G * 2) / 2;     printf( %.8lf n , A);   }   