(schoolwork) business math 8.5 table

local nprompt = function(q)
    print(q)
    term.blit("> ","3 ","  ")
    return tonumber(read())
end

local round = function(num)
    return math.floor((num*100)+0.5)/100
end

term.clear()
term.setCursorPos(1,1)

local amntOfMonths = 12 --nprompt("Length of loan? (months)")
local monthlyPayment = nprompt("Monthly payment?")
local principle = nprompt("Principle?")
local interestRate = nprompt("Interest rate?")/100
local payoffMonths = nprompt("Payoff after how long? (months)")
local totalMonths = nprompt("Total months of loan?")

local getIt = function(payoffMonths)

    output = {{}}
    output[1].interest = principle * interestRate * (1/amntOfMonths)
    output[1].principle = monthlyPayment - output[1].interest
    output[1].newPrinciple = principle - output[1].principle

    for a = 2, payoffMonths do
        output[a] = {}
        output[a].interest = output[a-1].newPrinciple * interestRate * (1/amntOfMonths)
        output[a].principle = monthlyPayment - output[a].interest
        output[a].newPrinciple = output[a-1].newPrinciple - output[a].principle
    end

    output[#output].principle = output[#output-1].newPrinciple
    output[#output].newPrinciple = 0
    finalPayment = output[#output].interest + output[#output].principle
    return output,finalPayment
end

local printOutput = function(output,finalPayment)

    local max = {}
    for a = 1, #output do
        max.interest = math.max(#tostring(output[a].interest), max.interest or 0)
        max.principle = math.max(#tostring(output[a].principle), max.principle or 0)
        max.newPrinciple = math.max(#tostring(output[a].newPrinciple), max.newPrinciple or 0)
    end
    for k,v in pairs(max) do
        max[k]=v+1
    end

    term.setCursorPos(1,1)
    term.write("Int.")
    term.setCursorPos(max.interest+1,1)
    term.write("Pri.")
    term.setCursorPos(max.interest+max.principle+1,1)
    term.write("NewPri.")

    for a = 1, #output do
        term.setCursorPos(1,a+1)
        term.write(round(output[a].interest))
        term.setCursorPos(max.interest+1,a+1)
        term.write(round(output[a].principle))
        term.setCursorPos(max.interest+max.principle+1,a+1)
        term.write(round(output[a].newPrinciple))
    end

    term.setCursorPos(1,#output+3)

    print("Final payment: "..tostring(round(finalPayment)))
end

local tab1, finalPay1 = getIt(payoffMonths)
local tab2, finalPay2 = getIt(totalMonths)
term.clear()
printOutput(tab1,finalPay1)
print("You saved: "..round(finalPay1-finalPay2))