func_code_string: #include <bits/stdc++.h>   using namespace std;   int sqr(int v) { return v * v; }   int main() {     int x1, y1, x2, y2, r1, r2;     cin >> x1 >> y1 >> r1 >> x2 >> y2 >> r2;     if (r1 < r2) swap(x1, x2), swap(y1, y2), swap(r1, r2);     int t1 = sqr(x1 - x2) + sqr(y1 - y2);     long double ans(0);     if (t1 < sqr(r1 - r2))       ans = r1 - r2 - sqrt((long double)t1);     else if (t1 > sqr(r1 + r2))       ans = sqrt((long double)t1) - r1 - r2;     cout << fixed << setprecision(20) << ans / 2 << endl;   }   