Safe Division

Check divisors before division so invalid input has a predictable result.

safe_division.lua

local divisor = 
local ok = divisor ~= 0
local display = "undefined"

if ok then
  display = tostring(12 / divisor)
end

print("divisor=" .. divisor)
print("ok=" .. tostring(ok))
print("display=" .. display)

local divisor = 
local ok = divisor ~= 0
local display = "undefined"

if ok then
  display = tostring(12 / divisor)
end

print("divisor=" .. divisor)
print("ok=" .. tostring(ok))
print("display=" .. display)

local divisor = 
local ok = divisor ~= 0
local display = "undefined"

if ok then
  display = tostring(12 / divisor)
end

print("divisor=" .. divisor)
print("ok=" .. tostring(ok))
print("display=" .. display)

safe alternative When failure is expected for some inputs, make the invalid case a visible branch with a stable fallback value.