CurrencyConverter.java

import java.util.Scanner;

class CurrencyConverter {
	private static double rate;
	
	public static double toDollar(double won) {
		return won/rate;
	}
	public static double toKRW(double dollar) {
		return dollar*rate;
	}
	public static void setRate(double r) {
		rate = r;
	}
}
public class CurrencyConverterTest {
	public static void main(String[] args) {
		Scanner scanner = new Scanner(System.in);
		
		System.out.print("Exchange rate($1) >> ");
		double rate = scanner.nextDouble();
		CurrencyConverter.setRate(rate);
		
		System.out.printf("%,d KRW = $%,.2f\n", 100000, CurrencyConverter.toDollar(100000));
		System.out.printf("$%,d = %, d KRW\n", 100, (int)CurrencyConverter.toKRW(100));
		
		scanner.close();
	}
}