func_code_string: #include <bits/stdc++.h>   using namespace std;   int main() {     long a, b, c, r, d, t, x1 = 0, x2 = 0;     cin >> t;     while (t--) {       cin >> a >> b >> c >> r;       d = 0;       if (a > b) {         swap(a, b);       }       x1 = c - r;       x2 = c + r;       if (x2 < a || x1 > b) {         d = b - a;       } else if (x1 <= a && x2 >= b) {         d = 0;       } else {         if (a <= x1) {           d += x1 - a;         }         if (b >= x2) {           d += b - x2;         }       }       cout << d << endl;     }   }   