decrypter

table1 = {"a","b","c","d","e","f","g","h","i","j","k","l","m","n","o","p","q","r","s","t","u","v","w","x","y","z"}
table2 = {}
table3 = {}
output = ""
shell.run("clear")
print("enter the offset")
offset = tonumber(read())
print("enter the text")
input = read()

if offset < 26 then


for x=1, #table1+offset do
if x <= #table1 then
table.insert(table2,table1[x+offset])
else
table.insert(table2,table1[x-#table1])
end
end


for x=1,string.len(input) do
char = string.sub(input,x,x)
table.insert(table3,char)
end

for x=1,#table3 do
    for z=1,#table2 do
        if table2[z] == table3[x] then
        output = output..table1[z]
        end
    end
end
print("the decrypted text:")
print(output)
else
print("ERROR offset over 26")
end