View Compilation Error

0_0_21316723_20239.cpp: In member function 'void fastIO::Ostream_fwrite::print(double, int)':
0_0_21316723_20239.cpp:148:30: error: 'floor' was not declared in this scope
             ll x1=(ll)floor(x); if (x-floor(x)>=0.5)++x1;
                              ^