x = 123

#think simple
if x < 0
    throw("Number less than zero.")
elseif x >= 0 && x < 10
    println("Number has one digit.")
elseif x >= 10 && x < 100
    println("Number has two digit.")
elseif x >= 100 && x < 1000
    println("Number has three digit.")
else
    println("Number has more than three digits.")
end

##### Or with the number of digits as before

if x>0
    digits = round(Int,log10(x))+1
    if digits > 3
        println("Number has more than three digits.")
    elseif digits == 1
        println("Number has one digit.")
    else
        println("Number has $digits digits.")
    end
elseif x==0
    println("Number has one digit.")
else
    throw("Number less than zero.")
end