每日一题（17）

public class Name {
    private final  String first, last;

    public Name(String first, String last){
        this.first = first;
        this.last = last;
    }

    @Override
    public  boolean equals(Object o){
        if(o instanceof Name){
            return  false;
        }
        Name n = (Name)o;
        return n.first.equals(first) && n.last.equals(last);
    }

    public static  void main(String[] args){
        Set<Name> s = new HashSet<>();
        s.add(new Name("Mickey", "Mouse"));
        System.out.println(
                s.contains(new Name("Mickey", "Mouse")));
    }
}
//out
false

public class Question18 {
    public static void main(String[] args){
        String str = new String("test");
        System.out.print(str.toString());
    }
}

class String {
    private final java.lang.String str;

    String(java.lang.String str){
        this.str = str;
    }

    @Override
   public java.lang.String toString(){
       return str;
   }
}