private Rank rank;
private Suit suit;
private int value;

這三行就怪怪的
enum類別有final特性
你這樣定義..?

再來
compile error是:

Card.java:39: incompatible types
found : java.lang.String
required: Card.Suit
this.suit = suit;
^
Card.java:40: incompatible types
found : java.lang.String
required: Card.Rank
this.rank = rank;
^
Card.java:50: incompatible types
found : Card.Suit
required: java.lang.String
return this.suit;
^
Card.java:59: incompatible types
found : Card.Rank
required: java.lang.String
return this.rank;
^
4 errors


你的getSuit,getRank
return type是String
getValue是 int

而enum的值根據書本
不可是int或String

可能可以用valueOf()來取得和名稱相同的值
如Rank.valueOf("DEUCE")

不保證對喔