ivy/doc/sample/CaesarCipher.im

package net.doorstuck.test

cout put:'Encode a string with a Caesar cipher.'

message = ''

while true do
    cout print:'Message to encode: '
    cout flush

    cin get:message

    if message != '' then
        break
    end
end

shift-width = 0

while true do
    cout print:'Shift size: '
    cout flush

    shift-str = cin read-line.

    if shift-str == '' then
        continue
    end

    try
        shift-width = Int parse:shift-str
    catch ($err:number-format, err)
        continue
    end

    break
end

encoded-message = ''

for c in message do
    i = c to-ordinal
    sub = 0

    if i >= 65 && i <= 90 then
        sub = 65
    elif i >= 97 && i <= 122 then
        sub = 97
    else
        continue
    end

    i -= sub
    i += shift-width

    if i >= 26 then
        i -= 26
    end

    c2 = i to-char
    encoded-message += c2
end

cout put:encoded-message