/*
 * Functions useful for dealing with interest accumulation.
 */
#include <stdio.h>

/* Print a table showing interest accumulation */

void printBalances(double intrate, double balance, int period)
{
  double yearEndBalance(double monthly_bal, double interest_rate);

  int year;

  for (year = 1; year <= period; year = year + 1)
  {
    balance = yearEndBalance(balance, intrate);
    printf("%4i   $ %7.2f\n", year, balance);
  }
}

/* Compute a year's ending balance, compounding interest monthly */

double yearEndBalance(double monthly_bal, double interest_rate)
{
  double  monthly_intrate;              /* % interest per month */
  int     month;                        /* current month */

  monthly_intrate = interest_rate / 12;
  for (month = 1; month <= 12; month = month + 1)
    monthly_bal = monthly_bal * monthly_intrate + monthly_bal;
  return monthly_bal;
}