Lab 4 : Loan payment

void setup() {
  loan_payment(5000, 0.05, 12);
}
void loan_payment(float amount, float rate, int month) {
  float rate_permonth = rate/month;
  float pay_permonth = amount*(rate_permonth/(1-pow(1+rate_permonth, -month)));
  float principal = pay_permonth;
  float remain = amount;
  int x = 1;
  println("No.  Beginning Balance    Interest      Principal     Ending Balance");
  while (x <= month) {
    print(nf(x, 2)); //Num
    print("     "+nf(remain, 4, 2)); //remain
    principal = pay_permonth-(rate_permonth*remain);
    remain -= principal;
    if (remain < 0) {
      remain = 0;
    }
    print("             "+nf(rate_permonth*remain, 2, 2)); //Principal
    print("         "+nf(principal, 3, 2)); //Unpaid
    print("         "+nf(remain, 4, 2)); //Total
    x++;
  }
}