// LOANSKED.CPP by J. W. Rider [950302]

// Generate loan payment schedule

#include <math.h> // pow()

#include <iostream.h>

#include <iomanip.h> // setprecision(), setw()

void loan_schedule(double principal, // dollars

double interest_rate, // percentage annually

double term_years,

double compounding_periods_per_year); // 12 = monthly

int main(int argc,char *argv[])

{

double inprincipal, inrate, interms;

if (argc > 1)

inprincipal = atof(argv[1]);

else {

cout << endl << "Amount of loan:$";

cin >> inprincipal;

}

if ( inprincipal< 0.005) {

cout << "Bad loan amount!" << endl;

return 1;

}

if (argc > 2)

inrate = atof(argv[2]);

else {

cout << "Annual interest rate(%):";

cin >> inrate;

}

if ( inrate < 1) inrate *= 100;

if ( inrate< 1) {

cout << "Bad interest rate!" << endl;

return 1;

}

if (argc > 3)

interms = atof(argv[3]);

else {

cout << "Number of years:";

cin >> interms;

}

if ( interms< 0.005) {

cout << "Bad number of years!" << endl;

return 1;

}

loan_schedule( inprincipal, inrate, interms, 12);

return 0;

}

void loan_schedule(double principal, // dollars

double interest_rate, // percentage annually

double term_years,

double compounding_periods_per_year) // 12 = monthly

{

double irate; // interest rate

double term; // number of compounding periods for life of loan

double paymt; // payment per compounding period.

int paymentnum; // number of payments

double balance; // running remaining principal to be paid

double totalpayment; // accumulated payments

double totalipaid; // accumulated interest paid

double totalppaid; // accumulated principal paid

// Generate header

cout << endl;

cout << "Loan Payback Schedule" << endl;

cout << "on $" << setprecision(2) << principal ;

cout << " at " << interest_rate << "%" ;

cout << " annually for " << term_years << " year(s)" << endl ;

if (fabs(compounding_periods_per_year - 1) > 0.0001) {

cout << "compounded " << compounding_periods_per_year;

cout << " times per year" << endl;

}

cout << endl;

cout << "PAYMENT # ";

cout << "BALANCE ";

cout << "PAYMENT ";

cout << "INTEREST PAID ";

cout << "PRINCIPAL PAID ";

cout << "REMAINING";

cout << endl << endl;

// Initialize variables for loop

irate = interest_rate/(100*compounding_periods_per_year);

term = term_years*compounding_periods_per_year;

paymt = ceil(100*principal*irate*pow(1+irate,term)

/(pow(1+irate,term)-1))

/100;

paymentnum = 0;

balance = principal;

totalpayment = 0;

totalipaid = 0;

totalppaid = 0;

cout.setf(ios::fixed | ios::showpoint);

cout.precision(2);

// Report each period's payment

while (balance>0.005) { // need to pay if more 1/2 cent outstanding

cout << setw(9) << ++paymentnum;

cout << setw(9) << balance;

if (paymt > balance*(1+irate))

paymt = ceil(100*balance*(1+irate)-0.5)/100;

cout << setw(9) << paymt;

totalpayment += paymt;

cout << setw(15) << balance*irate ;

totalipaid += balance*irate;

cout << setw(16) << (paymt-balance*irate);

totalppaid += paymt - balance*irate;

balance -= paymt - balance*irate;

cout << setw(11) << balance;

cout << endl;

}

// Summarize loan payments

cout << endl;

cout << "Total payments: " << paymentnum << endl;

cout << "Total paid: $" << setw(14) << totalpayment << endl;

cout << "Interest paid: $" << setw(14) << totalipaid << endl;

cout << "Principal paid: $" << setw(14) << totalppaid << endl;

}