Lua Function stuck in a loop - function

Question

I'm using the standard lua 5.4.4 distribution and interpreter, no libraries, etc.
I'm attempting to write a script to evaluate user defined values of the Collatz Conjecture
(TLDR at the bottom)
I want the script to read a user input (this part works so I didn't include it)
and based on that input, set a starting number (ognumber), and a range of numbers to try
then, i want it to iterate through every number between the ognumber and the range (in increments of 1)
for every iteration, i want it to check if each number is odd or even, do some math with the result being "newnumber", then set number = newnumber to try the result of the previous operation.
The problem I'm facing is that when I call the function, it doesn't end.
it gets stuck continuously trying the same number, it doesn't return number, and it doesn't set number = newnumber.
function isodd(number, newnumber, ResultsPath, results)
newnumber = math.floor(number * 3 + 1)
print(number..' x 3 + 1 = '..newnumber)
local writetoresultsfile = io.open(ResultsPath..'3n+1-'..results..'.xml', 'a')
writetoresultsfile:write(' '..number..' x 3 + 1 = '..newnumber..'\n')
writetoresultsfile:close()
number = math.floor(newnumber)
return number
end
function iseven(number, newnumber, ResultsPath, results)
newnumber = math.floor(number / 2)
print(number..' / 2 = '..newnumber)
local writetoresultsfile = io.open(ResultsPath..'3n+1-'..results..'.xml', 'a')
writetoresultsfile:write(' '..number..' / 2 = '..newnumber..'\n')
writetoresultsfile:close()
number = math.floor(newnumber)
return number
end
for number = ognumber, range, 1 do
local writetoresultsfile = io.open(ResultsPath..'3n+1-'..results..'.xml', 'a')
writetoresultsfile:write(' <List name = "Attempt '..ognumber..'"> \n')
writetoresultsfile:close()
print('Trying '..number)
while(number > 1) do
if(number % 2 ~= 0) then
isodd(number, newnumber, ResultsPath, results)
else
iseven(number, newnumber, ResultsPath, results)
end
end
ognumber = ognumber + 1
number = ognumber
end
if(ognumber == range + 1) then
local resultsfile = io.open(ResultsPath..'3n+1-'..results..'.xml', 'a')
resultsfile:write(' </Table>\n')
resultsfile:write('</Data>\n')
resultsfile:close()
end
This is what shows up when I run the script using function()
This script works, but I wanted to achieve the same thing using functions
for number = ognumber, range, 1 do
local writetoresultsfile = io.open(ResultsPath..'3n+1-'..results..'.xml', 'a')
writetoresultsfile:write(' <List name = "Attempt '..ognumber..'"> \n')
writetoresultsfile:close()
print('Trying '..number)
while(number > 1) do
if(number % 2 ~= 0) then
newnumber = math.floor(number * 3 + 1)
print(number..' x 3 + 1 = '..newnumber)
local writetoresultsfile = io.open(ResultsPath..'3n+1-'..results..'.xml', 'a')
writetoresultsfile:write(' '..number..' x 3 + 1 = '..newnumber..'\n')
writetoresultsfile:close()
number = newnumber
else
newnumber = math.floor(number / 2)
print(number..' / 2 = '..newnumber)
local writetoresultsfile = io.open(ResultsPath..'3n+1-'..results..'.xml', 'a')
writetoresultsfile:write(' '..number..' / 2 = '..newnumber..'\n')
writetoresultsfile:close()
number = newnumber
end
end
ognumber = ognumber + 1
number = ognumber
end
if(ognumber == range + 1) then
local resultsfile = io.open(ResultsPath..'3n+1-'..results..'.xml', 'a')
resultsfile:write(' </Table>\n')
resultsfile:write('</Data>\n')
resultsfile:close()
end
This is what it shows when I don't use function()
Edit: This Script works using the advice Shingo gave me
function isodd(number, ResultsPath, results)
newnumber = math.floor(number * 3 + 1)
print(number..' x 3 + 1 = '..newnumber)
local writetoresultsfile = io.open(ResultsPath..'3n+1-'..results..'.xml', 'a')
writetoresultsfile:write(' '..number..' x 3 + 1 = '..newnumber..'\n')
writetoresultsfile:close()
number = math.floor(newnumber)
return number
end
function iseven(number, ResultsPath, results)
newnumber = math.floor(number / 2)
print(number..' / 2 = '..newnumber)
local writetoresultsfile = io.open(ResultsPath..'3n+1-'..results..'.xml', 'a')
writetoresultsfile:write(' '..number..' / 2 = '..newnumber..'\n')
writetoresultsfile:close()
number = math.floor(newnumber)
return number
end
for number = ognumber, range, 1 do
local writetoresultsfile = io.open(ResultsPath..'3n+1-'..results..'.xml', 'a')
writetoresultsfile:write(' <List name = "Attempt '..ognumber..'"> \n')
writetoresultsfile:close()
print('Trying '..number)
while(number > 1) do
if(number % 2 ~= 0) then
number = isodd(number, ResultsPath, results)
else
number = iseven(number, ResultsPath, results)
end
end
ognumber = ognumber + 1
number = ognumber
end
if(ognumber == range + 1) then
local resultsfile = io.open(ResultsPath..'3n+1-'..results..'.xml', 'a')
resultsfile:write(' </Table>\n')
resultsfile:write('</Data>\n')
resultsfile:close()
end
TLDR about the Collatz Conjecture for those interested:
The Collatz Conjecture states that for any positive integer, if you apply 2 rules to it, will always return to 1.
The rules are: if the previous number is even, the next number is one half of the previous number. If the previous number is odd, the next number is 3 times the previous number plus 1

Answer 1

Although you return number from the function, it won't be updated out of the scope, you need accept it like this (same as iseven):
number = isodd(number, newnumber, ResultsPath, results)
Moreover newnumber is only used inside the function, so it's not necessary to be an argument. The function could be change to:
function isodd(number, ResultsPath, results)
local newnumber = math.floor(number * 3 + 1)