RosettaCodeData/Task/Straddling-checkerboard/Lua/straddling-checkerboard.lua

73 lines
2.0 KiB
Lua

local brd = { "HOL MES RT", "ABCDFGIJKN", "PQUVWXYZ./" }
local dicE, dicD, s1, s2 = {}, {}, 0, 0
function dec( txt )
local i, numb, s, t, c = 1, false
while( i < #txt ) do
c = txt:sub( i, i )
if not numb then
if tonumber( c ) == s1 then
i = i + 1; s = string.format( "%d%s", s1, txt:sub( i, i ) )
t = dicD[s]
elseif tonumber( c ) == s2 then
i = i + 1; s = string.format( "%d%s", s2, txt:sub( i, i ) )
t = dicD[s]
else
t = dicD[c]
end
if t == "/" then
numb = true
else
io.write( t )
end
else
io.write( c )
numb = false
end
i = i + 1
end
print()
end
function enc( txt )
local c
for i = 1, #txt do
c = txt:sub( i, i )
if c >= "A" and c <= "Z" then
io.write( dicE[c] )
elseif c >= "0" and c <= "9" then
io.write( string.format( "%s%s", dicE["/"], c ) )
end
end
print()
end
function createDictionaries()
for i = 1, 10 do
c = brd[1]:sub( i, i )
if c == " " then
if s1 == 0 then s1 = i - 1
elseif s2 == 0 then s2 = i - 1 end
else
dicE[c] = string.format( "%d", i - 1 )
dicD[string.format( "%d", i - 1 )] = c
end
end
for i = 1, 10 do
dicE[brd[2]:sub( i, i )] = string.format( "%d%d", s1, i - 1 )
dicE[brd[3]:sub( i, i )] = string.format( "%d%d", s2, i - 1 )
dicD[string.format( "%d%d", s1, i - 1 )] = brd[2]:sub( i, i )
dicD[string.format( "%d%d", s2, i - 1 )] = brd[3]:sub( i, i )
end
end
function enterText()
createDictionaries()
io.write( "\nEncrypt or Decrypt (E/D)? " )
d = io.read()
io.write( "\nEnter the text:\n" )
txt = io.read():upper()
if d == "E" or d == "e" then enc( txt )
elseif d == "D" or d == "d" then dec( txt )
end
end
-- entry point
enterText()