/*rexx*/
say "enter loan amount"
parse pull principal
/*I used this format to input the rest of the information*/
if principal =0 THEN do
say "congrats you're debt-free!"
exit
end
if principal <0 then do
do until principal >0
say "loan amount must be greater than 0"
say "enter loan amount"
parse pull principal
end
end
/*create two principals for roi comparison*/
principal1=principal
principal2=principal
say "your loan amount is " principal
/*loan intrest rate*/
say "enter loan intrest rate"
parse pull Irate
if irate <0 then do
do until irate >=0
say "intrest rate must be greater than 0"
say "enter intrest rate"
parse pull irate
end
end
say "your intrest rate is " irate "%"
/*loan term in years*/
say "enter your loan term in whole years "
parse pull time
if time <1 then
do until time >=1
say " term in years must be greater than 0"
say "enter your loan term in years"
parse pull time
end
rate= ((irate/100)/12) /*periodic intrest rate*/
/*roi loop*/
time=time*12
payment = principal1*((rate*(1+rate)**time)/(((1+rate)**time)-1))
totali1 =0
do until principal1 <=payment
intrest = rate* principal1
totali1= totali1+intrest
principal1 = principal1+intrest -payment
end
intrest = rate* principal1
payment= principal1+intrest
totali1= totali1 +intrest
principal1 = principal1+intrest -payment
/*loop end*/
/*optional addtional payments*/
say "youre on track to pay "totali1" in intrest ,how much extra would you like to pay each month ?(Enter zero if none)"
parse pull addpay
say "would you like your payment details to be executed to html(1) or excel((2)"
parse pull datatype
if datatype = 1 then do
outfile = "loan_report.html"
call lineout outfile, ""
call lineout outfile, ""
call lineout outfile, "Loan Amortization Schedule
"
call lineout outfile, ""
call lineout outfile, "| Payment # | Beginning Balance | Scheduled Payment | Extra Payment | Total Payment | Interest | Ending Balance | Total Interest |
|---|
"
end
if datatype = 2 then do
outfile = "loan_report.csv"
call lineout outfile, "Payment #,Beginning Balance,Scheduled Payment,Extra Payment,Total Payment,Interest,Ending Balance,Total Interest"
end
/*for a monthly compounded intrest i used the investopedia ammorizarion formula (Allred, 2025) ;A = P * (i * (1 + i) ^ n)/((1 + i) ^ n - 1)*/
totalp=0
totali= 0
count =0
totala=0
endbal=0
/*loan payoff loop*/
payment = principal2*((rate*(1+rate)**time)/(((1+rate)**time)-1))
do until principal2 <=payment
intrest = rate* principal2
count=count+1
totali= totali +intrest
totalp= totalp +payment+addpay
totala=totala+addpay
endbal= intrest+principal2-payment-addpay
if datatype = 1 then do
line = "| "count" | "trunc(principal2,2)" | "trunc(payment,2)" | "addpay" | "trunc(payment+addpay,2)" | "trunc(intrest,2)" | "trunc(endbal,2)" | "trunc(totali,2)" |
"
call lineout outfile, line
end
if datatype = 2 then do
line = count","trunc(principal2,2)","trunc(payment,2)","addpay","trunc(payment+addpay,2)","trunc(intrest,2)","trunc(endbal,2)","trunc(totali,2)
call lineout outfile, line
end
principal2 = endbal
end
/*loop ends*/
/*last payoff squence*/
addpay= 0
intrest = rate* principal2
payment= principal2+intrest
count=count+1
totalp= totalp +payment+addpay
totali= totali +intrest
endbal= intrest+principal2-payment-addpay
if datatype = 1 then do
line = "| "count" | "trunc(principal2,2)" | "trunc(payment,2)" | "addpay" | "trunc(payment+addpay,2)" | "trunc(intrest,2)" | "trunc(endbal,2)" | "trunc(totali,2)" |
"
call lineout outfile, line
end
if datatype = 2 then do
line = count","trunc(principal2,2)","trunc(payment,2)","addpay","trunc(payment+addpay,2)","trunc(intrest,2)","trunc(endbal,2)","trunc(totali,2)
call lineout outfile, line
end
principal2=intrest+principal2-payment-addpay
/* Final summary section */
save = trunc(totali1 - totali, 2)
roi = trunc((save / (totali1 + principal)) * 100, 2)
if datatype = 1 then do
call lineout outfile, "
"
call lineout outfile, "Final Summary
"
call lineout outfile, "Total payments made: " trunc(totalp, 2) "
"
call lineout outfile, "Total interest paid: " trunc(totali, 2) "
"
if addpay > 0 then
call lineout outfile, "Extra paid: " trunc(totala, 2) " over " count " months. Interest saved: " save ". ROI: " roi "%
"
call lineout outfile, ""
end
if datatype = 2 then do
call lineout outfile, ""
call lineout outfile, "Final Summary"
call lineout outfile, "Total payments made," trunc(totalp, 2)
call lineout outfile, "Total interest paid," trunc(totali, 2)
if addpay > 0 then
call lineout outfile, "Extra paid," trunc(totala, 2) ",Months," count ",Interest saved," save ",ROI," roi "%"
end
/* make sure to close output file */
call lineout outfile, , 1