If anyone has a simple 1d euler code which handles multi-material problems, please give me it just for reference. I really need to figure out that in this month. Help me. I cannot figure it out.

http://public.lanl.gov/aslam/cam98-17.pdf gives the formulation for Euler equation.

Thanks for your concern. I have had all references and books including the paper you linked. I believe I fully understood the theory but a problem is the implementation of it when two phase fluids exist. If you have had experiences about the implementation of the GFM(e.g. 1D shock tube problem), can we discuss about it? Anyway thanks about your concerns.