func_code_string: #include <bits/stdc++.h>   using namespace std;   double a, b, c, s, r;   double A, B, C;   double eps = 1e-3;   double pi = acos(-1.0);   struct Point {     double x, y;   } p[10];   double disP2P(Point a, Point b) {     return sqrt((a.x - b.x) * (a.x - b.x) + (a.y - b.y) * (a.y - b.y));   }   int sgn(double x) {     if (fabs(x) < eps) return 0;     if (x > 0) return 1;     return -1;   }   double fgcd(double a, double b) {     if (sgn(b) == 0) return a;     return fgcd(b, fmod(a, b));   }   int main() {     for (int i = 0; i < 3; ++i) {       cin >> p[i].x >> p[i].y;     }     a = disP2P(p[0], p[1]);     b = disP2P(p[1], p[2]);     c = disP2P(p[2], p[0]);     double x = (a + b + c) / 2;     s = sqrt(x * (x - a) * (x - b) * (x - c));     r = a * b * c / 4 / s;     A = acos(1 - a * a / 2 / r / r);     B = acos(1 - b * b / 2 / r / r);     C = 2 * pi - A - B;     double ang = fgcd(A, fgcd(B, C));     double ans = pi / ang * r * r * sin(ang);     printf( %.7f n , ans);   }   