refact-5.java

class Account {
	float principal;
	float rate;
	int daysActive;
	int accountType;

	public static final int STANDARD = 0;
	public static final int BUDGET = 1;
	public static final int PREMIUM = 2;
	public static final int PREMIUM_PLUS = 3;

	static final double BROKER_FEE_PERCENT = 0.0125;

	public boolean isPremium() {
		if (accountType == Account.PREMIUM || accountType == Account.PREMIUM_PLUS) {
			return true;
		}
		else {
			return false;
		}
	}

	float interestEarned( ) {
		float years = daysActive / (float) 365.25;
		float compoundInterest = principal * (float) Math.exp(rate * years);
		return (compoundInterest - principal);
	}

	float calculateFee(Account accounts[]) {
		float totalFee = 0;
		Account account;
		for (int i = 0; i < accounts.length; i++) {
			account = accounts[i];
			if (account.isPremium()) {
				totalFee += BROKER_FEE_PERCENT * account.interestEarned();
			}
		}
	    return totalFee;
	}
}