func_code_string: #include <bits/stdc++.h>   using namespace std;   const long long INF = 0x3fffffff;   double a, b, c, d;   int main() {     while (cin >> a >> b >> c >> d) {       double l = 0, r = 2000000000.0;       double a1, a2, b1, b2, c1, c2, d1, d2;       double m1, m2, min1, min2;       for (int i = 0; i < 10000; i++) {         double mid = (l + r) / 2;         a1 = a + mid, a2 = a - mid;         b1 = b + mid, b2 = b - mid;         c1 = c + mid, c2 = c - mid;         d1 = d + mid, d2 = d - mid;         min1 = min(min(a1 * d1, a1 * d2), min(a2 * d1, a2 * d2));         min2 = min(min(b1 * c1, b1 * c2), min(b2 * c1, b2 * c2));         m1 = max(max(a1 * d1, a1 * d2), max(a2 * d1, a2 * d2));         m2 = max(max(b1 * c1, b1 * c2), max(b2 * c1, b2 * c2));         if (min1 <= m2 && min2 <= m1)           r = mid;         else           l = mid;       }       printf( %.10lf n , l);     }     return 0;   }   