View Compilation Error

0_0_35981224_20593.cpp: In function 'void FFT(Complex*, const int&, const int&)':
0_0_35981224_20593.cpp:45:33: error: expected ')' before ';' token
         if (rev = getRev(i, len); i < rev)
                                 ^
0_0_35981224_20593.cpp:45:35: error: 'i' was not declared in this scope
         if (rev = getRev(i, len); i < rev)
                                   ^
0_0_35981224_20593.cpp:45:39: error: 'rev' was not declared in this scope
         if (rev = getRev(i, len); i < rev)
                                       ^