compilation error

[alchemist]

My system:
MacOS High Sierra
g++
onfigured with: --prefix=/Applications/Xcode.app/Contents/Developer/usr --with-gxx-include-dir=/usr/include/c++/4.2.1
Apple LLVM version 9.1.0 (clang-902.0.39.2)
Target: x86_64-apple-darwin17.7.0

FT.cpp:24:22: error: expected ')'
res[k] = (double complex) out[2k+1];
^
FFT.cpp:24:14: note: to match this '('
res[k] = (double complex) out[2k+1];
^
FFT.cpp:24:14: error: C-style cast from 'double ' to 'double' is not allowed
res[k] = (double complex) out[2k+1];
^~~~~~~~~~~~~~~~~~~~~~~~~~~
FFT.cpp:29:26: error: expected ')'
out[2k+1] = (double complex) val[k]/N;
^
FFT.cpp:29:18: note: to match this '('
out[2k+1] = (double complex) val[k]/N;
^
FFT.cpp:29:18: error: C-style cast from 'const double ' to 'double' is not allowed
out[2k+1] = (double complex) val[k]/N;
^~~~~~~~~~~~~~~~~~~~~~~
FFT.cpp:30:26: error: expected ')'
out[2k] = (double complex) 0;
^
FFT.cpp:30:18: note: to match this '('
out[2k] = (double complex) 0;
^
FFT.cpp:30:16: error: array type 'fftw_complex' (aka 'double [2]') is not assignable
out[2*k] = (double complex) 0;
~~~~~~~~ ^