View Compilation Error

0_0_24652947_3947.cpp: In function 'void fft(cd*, int, int)':
0_0_24652947_3947.cpp:92:46: error: lvalue required as left operand of assignment
  if(t==-1) for(int i=0;i<len;i++) a[i].real()=a[i].real()/len*1.0;
                                              ^