View Compilation Error

0_0_23462241_1612.cpp: In function 'void fft(std::complex<double>*, int, int)':
0_0_23462241_1612.cpp:32:45: error: lvalue required as left operand of assignment
  if(on==-1) for(int i=0;i<n;i++) a[i].real()/=n;
                                             ^