货币转换器

Question

这是我在这里的第一篇文章，2周前开始编程，我无法弄清楚，为什么扫描仪＆＃34;来自＆＃34;和＆＃34;到＆＃34;没有将答案与其中一个双打连接，似乎只是试图将其转换成一个数字，我很困惑。任何帮助表示赞赏:)！

    import java.util.Scanner;
    public class Main {
        public static void main(String[] args) {
            Scanner in = new Scanner(System.in);
            double BGN = 1;
            double USD = 1.79549;
            double EUR = 1.95583;
            double GBP = 2.53405;
            double money = Double.parseDouble((in.nextLine()));
            double from;
            from = Double.parseDouble((in.nextLine()));
            double to;
            to = Double.parseDouble((in.nextLine()));
            if (from == BGN && to == USD) {
                System.out.println((money * BGN) / USD + " USD");}
            else if (from == BGN && to == EUR){
                System.out.println((money * BGN) / EUR + " EUR");}
            else if (from == BGN && to == GBP){
                System.out.println((money * BGN) / GBP + " GBP");}
            else if (from == USD && to == BGN){
                System.out.println((money * USD) / BGN + " BGN");}
            else if (from == USD && to == EUR){
                System.out.println((money * USD) / EUR + " EUR");}
            else if (from == USD && to == GBP){
                System.out.println((money * USD) / GBP + " GBP");}
            else if (from == EUR && to == BGN){
                System.out.println((money * EUR) / BGN + " BGN");}
            else if (from == EUR && to == USD){
                System.out.println((money * EUR) / USD + " USD");}
            else if (from == EUR && to == GBP){
                System.out.println((money * EUR) / GBP + " GBP");}
            else if (from == GBP && to == BGN){
                System.out.println((money * GBP) / BGN + " BGN");}
            else if (from == GBP && to == USD){
                System.out.println((money * GBP) / USD + " USD");}
            else if (from == GBP && to == EUR){
                System.out.println((money * GBP) / EUR + " EUR");}
            else{
                System.out.println("Invalid Answer");}
        }
            }