Khan palindrome (iterative)

palindrome.jl

julia> function ispalindrome(S::String)
           i1 = 1
           i2 = length(S)
           while i2 > i1
               if S[i1] != S[i2]
                   println(S[i1])
                   println(S[i2])
                   return false # `false` is not a variable, that's why `return` is necessary
               end
               i1 += 1
               i2 -= 1
           end
           return true
       end
ispalindrome (generic function with 2 methods)

julia> ispalindrome("tat")
true

julia> ispalindrome("t") # base case 1
true

julia> ispalindrome("") # base case 2, `typeof("") => String`, correct behavior, but find out why
true
    
julia> ispalindrome("roter")
o
e
false

julia> ispalindrome("tatff")
t
f
false
                      
julia> ispalindrome("@@") # is this a palindrome?
true

julia> ispalindrome("ADA")
true

julia> ispalindrome("ADDa") # palindrome? 
A
a
false