I am working now in Beowulf Cluster and parallel processing, I want code for Fast Fourier transfer functions written in any language, e.g., C/C++. Without using FFTW library based on message passing interface method.
I would definitely advise going FFTW-route anyway. FFTW is a high-quality library with good documentation that can be used in a convenient way in your project without requiring many modifications or lots of additional code.
However, since you explicitly asked about an FFTW alternative, you can go Intel MKL route. Now, Intel Math Kernel Library offers Fourier Transform functions both for serial/shared memory, as well as for distributed memory cases.
Moreover, Intel MKL supports FFTW3 interfaces (at least for shared memory), so that you have an option of using FFTW through Intel MKL anyway.