window:233: bad argument #1 to 'floor' (number expected, got nil)

so what im trying to do is use variables to set and call data within a table and im getting this error. what do i do?
code:

x,y = term.getSize()
z = 5
while z > 0 do
z = z-1
zX[z] = math.random(x)
zY[z] = math.random(y)
end
zr = z
while zr > 0 do
zr = zr-1
term.setCursorPos(zX[zr],zY[zr])
term.setBackgroundColor(colors.green)
print(" ")
end

x doesn't have a value

y also doesn't

Lupus590, on 22 December 2015 - 12:28 AM said:

x doesn't have a value

y also doesn't

in the full program they do have a value

Can't see where that error would come from, but:

zr = z           -- z is 0 (because of the loop you just completed), and now zr is 0 too
while zr > 0 do  -- ... meaning this loop isn't going to do much

… so I'm going to go out on a limb and say that you're still not showing us the code you're actually running, which makes it rather difficult to point out what's wrong. Presumably you're somehow attempting to call term.setCursorPos() with an index of zX / zY that you never actually set.