Shell Programming and Scripting

How can i add a varying filename at the end of a constant file path?

Eg:
Variable containing file name is varfile (say varfile=newfile)
File path is C:\Test\

I want to access newfile which can be done as
C:/\Test/\newfile

But instead of directly accesing the newfile i want to access it through variable varfile?
How to add this varfile at the end of file path( C:/\Test/\ )

Suppose path is c:/test/sandeep
and file name is varfile
use this to access c:/test/sandeep/$varfile
the most generic use is to store constant path into var too
like
dir_path='/export/home/sandeep'
varfile=filename

if you want to use file then you can use in any command like

ls $dir_path/$varfile

Thanks alot

Please help