answer.code: In function ‘std::pair<std::vector<long double>, std::vector<std::vector<long double> > > gauss(std::vector<std::vector<long double> >&, int, int)’:
answer.code:16:80: error: expected ‘;’ before ‘j’
   16 |                 for (int k = j + 1; k < n; k++) if (abs(a[k][i] > abs(a[j][i])) j = k;
      |                                                                                ^~
      |                                                                                ;
answer.code:17:17: error: expected primary-expression before ‘if’
   17 |                 if (j == n || abs(a[j][i]) < eps) continue;
      |                 ^~
answer.code:16:87: error: expected ‘)’ before ‘if’
   16 |                 for (int k = j + 1; k < n; k++) if (abs(a[k][i] > abs(a[j][i])) j = k;
      |                                                    ~                                  ^
      |                                                                                       )
   17 |                 if (j == n || abs(a[j][i]) < eps) continue;
      |                 ~~