View Compilation Error

0_0_18750007_16972.cpp: In member function 'void Solution::solve(std::istream&, std::ostream&)':
0_0_18750007_16972.cpp:116:20: error: 'x' was not declared in this scope
     last = (double(x) / (int(double(gap - eps) / last) + 1));
                    ^