import java.util.Comparator;

class Comp {
    public static void main(String[] args) {
        System.out.println(max2(1,2));

        Person p1 = new Person(11);
        Person p2 = new Person(20);

        System.out.println(max2(p1,p2));

        System.out.println(max2(p1,p2,new PersonComp()));

        System.out.println(max2(p1,p2,new Comparator<Person>(){
            public int compare(Person a, Person b) {
                return b.alder - a.alder;
            }
        }));


    }

    public static <T extends Comparable<T>> T max2(T a, T b) {
        if (a.compareTo(b) > 0) return b;
        else return a;
    }

    public static <T> T max2(T a, T b, Comparator<T> comp) {
        if (comp.compare(a,b) > 0) return b;
        else return a;
    }
}

class Person implements Comparable<Person>{
    int alder;

    Person(int a) {
        alder = a;
    }

    public String toString() {
        return alder+"";
    }

    public int compareTo(Person p) {
        return alder - p.alder;
    }
}

class PersonComp implements Comparator<Person> {
    public int compare(Person a, Person b) {
        return (a.alder % 10) - (b.alder % 10);
    }
}