[julia-users] calling files in Julia

[new to Julia]

I have a question for calling files in Julia:

I have two jl files. And I can call one file from the other file. However, 
the variable or constant defined in that file cannot be used in the other 
file. I am wondering that how to fix this? The following is a simple 
example. 

function test(x)
  c=2;
  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)


However, when I run this test2, there is a error comes out: saying that c 
is not defined.

Thank you very much.