[julia-users] call variables defined in different jl file

[new to Julia]

Hi all:

I have two function files saved in two different jl file. I can call files. 
However, for variables defined in one file, I cannot use it in the other 
file. The following is a simple example: 

function test(x)
  y1=6*x;
  y2=x/5;
  y1,y2
end
pwd()



## test and test2 are used for calling functions in Julia
function test2(x)
  include("test.jl")
  yold,ynew=test(x/c);
  y3=yold+10;
  y4=ynew-10;
  yold2,ynew2=test(x)
  y5=yold2+20;
  y6=ynew2-20;
  y3,y4,y5,y6
end
y3,y4,y5,y6=test2(100)

when I run test2, it always comes an error: c is not defined. 

I am wondering that how to do with this? Thank you!