Calculator Alpha

--[[ Simple Calculator Designed by NDFJay for AnthonyD98, all rights are reserved for AnthonyD98 ]]--

local w,h = term.getSize()
local n = 17
local padY = 7
local equation = {"(", ")"}
term.clear()
local function center(text, line)
  term.setCursorPos(math.ceil(w/2)-string.len(text)/2, line)
  print(text)
end
local function calculate(eq)
 if table.concat(eq) == "()" then
  eq = {"0"}
 elseif table.concat(eq) == "(.)" then
  eq = {"0"}
 end
 local sExpr = table.concat(eq)
 local fnMath, sErr = loadstring("return "..sExpr)
 if not fnMath then
  return "ERROR 1: "..sErr
 end
 setfenv(fnMath, math)
 local bSucc, vRes = pcall(fnMath)
 if not bSucc then
  return "ERROR 2: "..vRes
 else
  return vRes
 end
end
local function draw()
center(string.rep("#",47),1)
center("#"..string.rep(" ",45).."#",2)
center("#"..string.rep(" ",45).."#",3)
center("#"..string.rep(" ",45).."#",4)
center(string.rep("#",47),5)
term.setCursorPos(5,2)
write(table.concat(equation))
term.setCursorPos(1, math.floor(h-1))
print('Press "Q" to exit')

end
local pad ={
        " [ / ] [ * ] [ - ] [ + ]";
        " [ 7 ] [ 8 ] [ 9 ] [ . ]";
        " [ 4 ] [ 5 ] [ 6 ] [   ]";
        " [ 1 ] [ 2 ] [ 3 ] [ = ]";
        "      [     0     ]     "
}

local function selected()
    if n == 1 then
pad ={
        " [>/<] [ * ] [ - ] [ + ]";
        " [ 7 ] [ 8 ] [ 9 ] [ . ]";
        " [ 4 ] [ 5 ] [ 6 ] [   ]";
        " [ 1 ] [ 2 ] [ 3 ] [ = ]";
        " [     0     ] [ Clear ]"
}
    elseif n == 2 then
pad ={
        " [ / ] [>*<] [ - ] [ + ]";
        " [ 7 ] [ 8 ] [ 9 ] [ . ]";
        " [ 4 ] [ 5 ] [ 6 ] [   ]";
        " [ 1 ] [ 2 ] [ 3 ] [ = ]";
        " [     0     ] [ Clear ]"
}
    elseif n == 3 then
pad ={
        " [ / ] [ * ] [>-<] [ + ]";
        " [ 7 ] [ 8 ] [ 9 ] [ . ]";
        " [ 4 ] [ 5 ] [ 6 ] [   ]";
        " [ 1 ] [ 2 ] [ 3 ] [ = ]";
        " [     0     ] [ Clear ]"
}
    elseif n == 4 then
pad ={
        " [ / ] [ * ] [ - ] [>+<]";
        " [ 7 ] [ 8 ] [ 9 ] [ . ]";
        " [ 4 ] [ 5 ] [ 6 ] [   ]";
        " [ 1 ] [ 2 ] [ 3 ] [ = ]";
        " [     0     ] [ Clear ]"
}
    elseif n == 5 then
pad ={
        " [ / ] [ * ] [ - ] [ + ]";
        " [>7<] [ 8 ] [ 9 ] [ . ]";
        " [ 4 ] [ 5 ] [ 6 ] [   ]";
        " [ 1 ] [ 2 ] [ 3 ] [ = ]";
        " [     0     ] [ Clear ]"
}
    elseif n == 6 then
pad ={
        " [ / ] [ * ] [ - ] [ + ]";
        " [ 7 ] [>8<] [ 9 ] [ . ]";
        " [ 4 ] [ 5 ] [ 6 ] [   ]";
        " [ 1 ] [ 2 ] [ 3 ] [ = ]";
        " [     0     ] [ Clear ]"
}
    elseif n == 7 then
pad ={
        " [ / ] [ * ] [ - ] [ + ]";
        " [ 7 ] [ 8 ] [>9<] [ . ]";
        " [ 4 ] [ 5 ] [ 6 ] [   ]";
        " [ 1 ] [ 2 ] [ 3 ] [ = ]";
        " [     0     ] [ Clear ]"
}
    elseif n == 8 then
pad ={
        " [ / ] [ * ] [ - ] [ + ]";
        " [ 7 ] [ 8 ] [ 9 ] [>.<]";
        " [ 4 ] [ 5 ] [ 6 ] [   ]";
        " [ 1 ] [ 2 ] [ 3 ] [ = ]";
        " [     0     ] [ Clear ]"
}
    elseif n == 9 then
pad ={
        " [ / ] [ * ] [ - ] [ + ]";
        " [ 7 ] [ 8 ] [ 9 ] [ . ]";
        " [>4<] [ 5 ] [ 6 ] [   ]";
        " [ 1 ] [ 2 ] [ 3 ] [ = ]";
        " [     0     ] [ Clear ]"
}
    elseif n == 10 then
pad ={
        " [ / ] [ * ] [ - ] [ + ]";
        " [ 7 ] [ 8 ] [ 9 ] [ . ]";
        " [ 4 ] [>5<] [ 6 ] [   ]";
        " [ 1 ] [ 2 ] [ 3 ] [ = ]";
        " [     0     ] [ Clear ]"
}
    elseif n == 11 then
pad ={
        " [ / ] [ * ] [ - ] [ + ]";
        " [ 7 ] [ 8 ] [ 9 ] [ . ]";
        " [ 4 ] [ 5 ] [>6<] [   ]";
        " [ 1 ] [ 2 ] [ 3 ] [ = ]";
        " [     0     ] [ Clear ]"
}
    elseif n == 12 then
pad ={
        " [ / ] [ * ] [ - ] [ + ]";
        " [ 7 ] [ 8 ] [ 9 ] [ . ]";
        " [ 4 ] [ 5 ] [ 6 ] [> <]";
        " [ 1 ] [ 2 ] [ 3 ] [>=<]";
        " [     0     ] [ Clear ]"
}
    elseif n == 13 then
pad ={
        " [ / ] [ * ] [ - ] [ + ]";
        " [ 7 ] [ 8 ] [ 9 ] [ . ]";
        " [ 4 ] [ 5 ] [ 6 ] [   ]";
        " [>1<] [ 2 ] [ 3 ] [ = ]";
        " [     0     ] [ Clear ]"
}
    elseif n == 14 then
pad ={
        " [ / ] [ * ] [ - ] [ + ]";
        " [ 7 ] [ 8 ] [ 9 ] [ . ]";
        " [ 4 ] [ 5 ] [ 6 ] [   ]";
        " [ 1 ] [>2<] [ 3 ] [ = ]";
        " [     0     ] [ Clear ]"
}
    elseif n == 15 then
pad ={
        " [ / ] [ * ] [ - ] [ + ]";
        " [ 7 ] [ 8 ] [ 9 ] [ . ]";
        " [ 4 ] [ 5 ] [ 6 ] [   ]";
        " [ 1 ] [ 2 ] [>3<] [ = ]";
        " [     0     ] [ Clear ]"
}
    elseif n == 16 then
pad ={
        " [ / ] [ * ] [ - ] [ + ]";
        " [ 7 ] [ 8 ] [ 9 ] [ . ]";
        " [ 4 ] [ 5 ] [ 6 ] [> <]";
        " [ 1 ] [ 2 ] [ 3 ] [>=<]";
        " [     0     ] [ Clear ]"
}
    elseif n == 17 then
pad ={
        " [ / ] [ * ] [ - ] [ + ]";
        " [ 7 ] [ 8 ] [ 9 ] [ . ]";
        " [ 4 ] [ 5 ] [ 6 ] [   ]";
        " [ 1 ] [ 2 ] [ 3 ] [ = ]";
        " [ >   0   < ] [ Clear ]"
}
    elseif n == 18 then
pad ={
        " [ / ] [ * ] [ - ] [ + ]";
        " [ 7 ] [ 8 ] [ 9 ] [ . ]";
        " [ 4 ] [ 5 ] [ 6 ] [   ]";
        " [ 1 ] [ 2 ] [ 3 ] [ = ]";
        " [     0     ] [>Clear<]"
}

    end
draw()
for i,v in ipairs(pad) do
    center(v,padY+i)
end
end
term.clear()
selected()
while true do
local event, key = os.pullEvent("key")
selected()
if key == keys.right then
    n = n+1
    if n >= 18 then n = 18 end
    selected()
        elseif key == keys.left then
            n = n-1
            if n <= 1 then n = 1 end
            selected()
                elseif key == keys.down then
                    n = n+4
                    if n >= 18 then n = 18 end
                    selected()
                        elseif key == keys.up then
                            n = n-4
                            if n <= 1 then n = 1 end
                            selected()
                                elseif key == keys.enter then
                                    if n == 1 then
                                    table.insert(equation, #equation, "/")
                                    selected()
                                        elseif n == 2 then
                                        table.insert(equation, #equation, "*")
                                        selected()

                                        elseif n == 3 then
                                        table.insert(equation, #equation, "-")
                                        selected()

                                        elseif n == 4 then
                                        table.insert(equation, #equation, "+")
                                        selected()

                                        elseif n == 5 then
                                        table.insert(equation, #equation, "7")
                                        selected()

                                        elseif n == 6 then
                                        table.insert(equation, #equation, "8")
                                        selected()

                                        elseif n == 7 then
                                        table.insert(equation, #equation, "9")
                                        selected()

                                        elseif n == 8 then
                                        table.insert(equation, #equation, ".")
                                        selected()

                                        elseif n == 9 then
                                        table.insert(equation, #equation, "4")
                                        selected()

                                        elseif n == 10 then
                                        table.insert(equation, #equation, "5")
                                        selected()

                                        elseif n == 11 then
                                        table.insert(equation, #equation, "6")
                                        selected()

                                        elseif n == 12 then
                                        selected()
                                        term.setCursorPos(5,4)
                                        print(calculate(equation))

                                        elseif n == 16 then
                                        selected()
                                        term.setCursorPos(5,4)
                                        print(calculate(equation))

                                        elseif n == 13 then
                                        table.insert(equation, #equation, "1")
                                        selected()

                                        elseif n == 14 then
                                        table.insert(equation, #equation, "2")
                                        selected()

                                        elseif n == 15 then
                                        table.insert(equation, #equation, "3")
                                        selected()

                                        elseif n == 17 then
                                        table.insert(equation, #equation, "0")
                                        selected()

                                        elseif n == 18 then
                                        if table.concat(equation) ~= "()" then
                                        table.remove(equation, #equation - 1)
                                        end
                                        selected()

                                    end
                                        elseif key == 2 or key == 79 then
                                        table.insert(equation, #equation, "1")
                                        selected()
                                            elseif key == 3 or key == 80 then
                                            table.insert(equation, #equation, "2")
                                            selected()
                                                elseif key == 4 or key == 81 then
                                                table.insert(equation, #equation, "3")
                                                selected()
                                                    elseif key == 5 or key == 75 then
                                                    table.insert(equation, #equation, "4")
                                                    selected()
                                                        elseif key == 6 or key == 76 then
                                                        table.insert(equation, #equation, "5")
                                                        selected()
                                                            elseif key == 7 or key == 77 then
                                                            table.insert(equation, #equation, "6")
                                                            selected()
                                                                elseif key == 8 or key == 71 then
                                                                table.insert(equation, #equation, "7")
                                                                selected()
                                                                    elseif key == 9 or key == 72 then
                                                                    table.insert(equation, #equation, "8")
                                                                    selected()
                                                                        elseif key == 10 or key == 73 then
                                                                        table.insert(equation, #equation, "9")
                                                                        selected()
                                                                            elseif key == 11 or key == 82 then
                                                                            table.insert(equation, #equation, "0")
                                                                            selected()
                                                                                elseif key == 52 or key == 83 then
                                                                                table.insert(equation, #equation, ".")
                                                                                selected()
                                                                                    elseif key == 53 or key == 181 then
                                                                                    table.insert(equation, #equation, "/")
                                                                                    selected()
                                                                                        elseif key == 53 or key == 181 then
                                                                                        table.insert(equation, #equation, "/")
                                                                                        selected()
                                                                                            elseif key == 55 then
                                                                                            table.insert(equation, #equation, "*")
                                                                                            selected()
                                                                                                elseif key == 74 then
                                                                                                table.insert(equation, #equation, "-")
                                                                                                selected()
                                                                                                    elseif key == 78 then
                                                                                                    table.insert(equation, #equation, "+")
                                                                                                    selected()
                                                                                                        elseif key == 14 then
                                                                                                        if table.concat(equation) ~= "()" then
                                                                                                        table.remove(equation, #equation - 1)
                                                                                                        end
                                                                                                        selected()
                                                                                                            elseif key == keys.q then
                                                                                                            term.clear()
                                                                                                            term.setCursorPos(1,1)
                                                                                                            break
end

end