Script to calculate taxes for biweekly paychecks

accounting.rb

#! /usr/bin/ruby

BUSINESS_TAX_SOCIAL_SECURITY = 0.062
EMPLOYEE_TAX_SOCIAL_SECURITY = 0.042

BUSINESS_TAX_MEDICARE        = 0.0145
EMPLOYEE_TAX_MEDICARE        = 0.0145

EMPLOYEE_TAX_INCOME_STATE    = 0.05

MONEY_FORMAT_STRING = "$%07.2f"

$employee_names                        = Array.new
$employee_gross_payments               = Array.new
$employee_social_security_tax_payments = Array.new
$employee_medicare_tax_payments        = Array.new
$employee_state_income_tax_payments    = Array.new
$employee_federal_income_tax_payments  = Array.new
$employee_net_payments                 = Array.new

$business_medicare_payment        = 0
$business_social_security_payment = 0

def run
  print "Business net income over period (after paying bills): "
  net_income = gets.chomp.to_f
  
  print "Number of employees: "
  employee_count = gets.chomp.to_f
  
  (1..employee_count).each do | i |
    print "Employee's name: "
    $employee_names += [gets.chomp]
    print "Gross pay:       "
    $employee_gross_payments += [gets.chomp.to_f]
  end
  
  # Calculate total amount going to employees / staying in business
  gross_payment = 0
  $employee_gross_payments.each do | employee_pay |
    gross_payment += employee_pay
  end
  net_income -= gross_payment # take gross payment away from net_income
  puts "Total gross pay is $#{gross_payment}, leaving $#{net_income}."
  
  $employee_gross_payments.each_index do | i |
  # puts "Employee #{i+1} earns #{employee_gross_pay[i]} gross pay."
    employee_pay = $employee_gross_payments[i]
    $employee_social_security_tax_payments += [employee_pay * EMPLOYEE_TAX_SOCIAL_SECURITY]
    $employee_medicare_tax_payments        += [employee_pay * EMPLOYEE_TAX_MEDICARE]
    $employee_state_income_tax_payments    += [employee_pay * EMPLOYEE_TAX_INCOME_STATE]
    $employee_federal_income_tax_payments  += [biweeklyFederalIncomeTax(:gross=>employee_pay, :isMarried=>false)]
    $employee_net_payments += [employee_pay -
                               $employee_social_security_tax_payments[i] -
                               $employee_medicare_tax_payments[i] -
                               $employee_state_income_tax_payments[i] -
                               $employee_federal_income_tax_payments[i]]
    
    $business_social_security_payment      +=  employee_pay * BUSINESS_TAX_SOCIAL_SECURITY
    $business_medicare_payment             +=  employee_pay * BUSINESS_TAX_MEDICARE
  end
  net_income -= $business_social_security_payment
  net_income -= $business_medicare_payment
  
  puts
  puts
  
  $employee_gross_payments.each_index do | i |
    puts "#{$employee_names[i]}"
    puts "  Gross:              #{sprintf(MONEY_FORMAT_STRING, $employee_gross_payments[i])}"
    puts "  Social Security:    #{sprintf(MONEY_FORMAT_STRING, $employee_social_security_tax_payments[i])}"
    puts "  Medicare:           #{sprintf(MONEY_FORMAT_STRING, $employee_medicare_tax_payments[i])}"
    puts "  State Income Tax:   #{sprintf(MONEY_FORMAT_STRING, $employee_state_income_tax_payments[i])}"
    puts "  Federal Income Tax: #{sprintf(MONEY_FORMAT_STRING, $employee_federal_income_tax_payments[i])}"
    puts "  Net:                #{sprintf(MONEY_FORMAT_STRING, $employee_net_payments[i])}"
    puts
  end
  
  puts "BUSINESS:"
  puts "  Social Security: #{sprintf(MONEY_FORMAT_STRING, $business_social_security_payment)}"
  puts "  Medicare:        #{sprintf(MONEY_FORMAT_STRING, $business_medicare_payment)}"
  puts "  Remaining:       #{sprintf(MONEY_FORMAT_STRING, net_income)}"
end

def weeklyFederalIncomeTax(params)
  gross = params[:gross]
  isMarried = params[:isMarried]
  
  if isMarried
    return    0.00                         if gross <   152.00
    return    0.00 + (gross -  152) * 0.10 if gross >=  152.00 and gross <  179.00
    return   32.70 + (gross -  479) * 0.15 if gross >=  479.00 and gross < 1479.00
    return  182.70 + (gross - 1479) * 0.25 if gross >= 1479.00 and gross < 1479.00
    return  520.95 + (gross - 2832) * 0.28 if gross >= 2832.00 and gross < 1479.00
    return  913.79 + (gross - 4235) * 0.33 if gross >= 4235.00 and gross < 1479.00
    return 1972.43 + (gross - 7443) * 0.35 if gross >= 7443.00
  else
    return    0.00                         if gross <    40.00
    return    0.00 + (gross -   40) * 0.10 if gross >=   40.00 and gross <  204.00
    return   16.40 + (gross -  204) * 0.15 if gross >=  204.00 and gross <  704.00
    return   91.40 + (gross -  704) * 0.25 if gross >=  704.00 and gross < 1648.00
    return  327.40 + (gross - 1648) * 0.28 if gross >= 1648.00 and gross < 3394.00
    return  816.28 + (gross - 3394) * 0.33 if gross >= 3394.00 and gross < 7332.00
    return 2115.82 + (gross - 7332) * 0.35 if gross >= 7332.00
  end
end

def biweeklyFederalIncomeTax(params)
  gross = params[:gross]
  isMarried = params[:isMarried]
  
  if isMarried
    return    0.00                          if gross <    304.00
    return    0.00 + (gross -   304) * 0.10 if gross >=   304.00 and gross <   958.00
    return   65.40 + (gross -   958) * 0.15 if gross >=   958.00 and gross <  2958.00
    return  365.40 + (gross -  2958) * 0.25 if gross >=  2958.00 and gross <  5663.00
    return 1041.65 + (gross -  5663) * 0.28 if gross >=  5663.00 and gross <  8469.00
    return 1827.33 + (gross -  8469) * 0.33 if gross >=  8469.00 and gross < 14887.00
    return 3945.27 + (gross - 14887) * 0.35 if gross >= 14887.00
  else
    return    0.00                          if gross <     81.00
    return    0.00 + (gross -    81) * 0.10 if gross >=    81.00 and gross <   408.00
    return   32.70 + (gross -   408) * 0.15 if gross >=   408.00 and gross <  1408.00
    return  182.70 + (gross -  1408) * 0.25 if gross >=  1408.00 and gross <  3296.00
    return  654.70 + (gross -  3296) * 0.28 if gross >=  3296.00 and gross <  6788.00
    return 1632.46 + (gross -  6788) * 0.33 if gross >=  6788.00 and gross < 14663.00
    return 4231.21 + (gross - 14663) * 0.35 if gross >= 14663.00
  end
end

run