circuitSolver

    --USAGE: 1:circuit type (p or s)  2:voltage total  3..:resistor values
    --Example: p 12 300 300 39000423 35184
local tArgs = {...}

    --Results table colors. Change if you want
local columbC = colors.green
local rowC = colors.green
local tableC = colors.white
local tableSpace = 11

term.clear()
term.setCursorPos(1,1)
local rCount = #tArgs-2

    --Input error checking
local inputError = "Usage: 1:circuit type (p or s)  2:voltage total  3..:resistor values"
if rCount <= 0 then
    error("rCount less than 0. "..inputError)
elseif tArgs[1] ~= "p" and tArgs[1] ~= "s" then
    error("p/s missing. "..inputError)
elseif not tonumber(tArgs[2]) then
    error("voltage value not a number: "..tArgs[2]..", "..type(tArgs[2])..". "..inputError)
elseif rCount >= 1 then
    for i = 3, #tArgs do
        if not tonumber(tArgs[i]) then
            error("resistor #"..i.." not a number: "..tArgs[i]..", "..type(tArgs[i])..". "..inputError)
        end
    end
end

    --E = volts, R = resistors, I = current, P = power
    --t = total
local E = { t = tArgs[2] }
local R = { t = 0 }
local I = { t = 0 }
local P = { t = 0 }

local function sci(x)
    return 1*10^(x)
end

local function formatE(x)
    if not tonumber(x) then error("Attempted to format non-number: "..x..", "..type(x)) end
    x = tonumber(x)
    local num
    local suffix = ""

    if     x >= sci(9) then --giga
        num = x / sci(9)
        suffix = "g"
    elseif x >= sci(6) then --mega
        num = x / sci(6)
        suffix = "M"
    elseif x >= sci(3) then --kilo
        num = x / sci(3)
        suffix = "k"
    elseif x >= 1 and x < 1000 then
        num = x
    elseif x <= 1*10^-9 then --nano
        num = x / sci(-9)
        suffix = "n"
    elseif x <= 1*10^-6 then --micro
        num = x / sci(-6)
        suffix = "u"
    elseif x < 1 then --milli
        num = x / sci(-3)
        suffix = "m"
    else error(x.." wasn't caught in formatting")
    end

    local mult = 10^(4)
    num = math.modf(num*mult)/mult

    return (num.." "..suffix)
end

    --solve a parallel circuit given resistors and voltage total
local function solveP()
        --Fill in ohms and voltage row
    local rBuffer = 0
    for i = 3, #tArgs do
        R[i-2] = tArgs[i]
        E[i-2] = E.t
            --Add up tArgs in buffer
        rBuffer = rBuffer + 1/tArgs[i]
    end
    R.t = 1/rBuffer

        --Get remaining totals
    I.t = E.t / R.t
    P.t = E.t * I.t
        --Fill in remaining rows
    for i = 1, rCount do
        I[i] = E[i] / R[i]
        P[i] = E[i] * I[i]
    end
end

    --solve a series circuit given resistors and voltage total
local function solveS()
        --Fill in ohms row
    for i = 3, #tArgs do
        R[i-2] = tArgs[i]
            --Add up tArgs to get resistor total
        R.t = R.t + tArgs[i]
    end
        --Get remaining totals
    I.t = E.t / R.t
    P.t = E.t * I.t
        --Fill in remaining rows
    for i = 1, rCount do
        I[i] = I.t
        E[i] = I[i] * R[i]
        P[i] = E[i] * I[i]
    end
end

local function solveCircuit() end
solveCircuit = solveS

    --Switch circuit type
if tArgs[1] == "p" then
    solveCircuit = solveP
end

    --Solve the selected circuit type
solveCircuit()

    --Print results table
term.setTextColor(columbC)
term.write("    Totals")
for i = 1, #tArgs-2 do
    term.setCursorPos((i*tableSpace)+4,1)
    term.write("R"..i)
end

print()
term.setTextColor(rowC)
term.write("E = ")
term.setTextColor(tableC)
print(formatE(E.t))

term.setTextColor(rowC)
term.write("R = ")
term.setTextColor(tableC)
print(formatE(R.t))

term.setTextColor(rowC)
term.write("I = ")
term.setTextColor(tableC)
print(formatE(I.t))

term.setTextColor(rowC)
term.write("P = ")
term.setTextColor(tableC)
print(formatE(P.t))

for i = 1, #tArgs-2 do
    local x = (i*tableSpace)+4
    term.setCursorPos(x,2)
    term.write(formatE(E[i]))

    term.setCursorPos(x,3)
    term.write(formatE(R[i]))

    term.setCursorPos(x,4)
    term.write(formatE(I[i]))

    term.setCursorPos(x,5)
    term.write(formatE(P[i]))
end
print()