컬렉션 프레임 워크

package test;
import java.util.*;
 
public class ArrayList {
 
    public static void main(String[] args) {
        List<String> list = new LinkedList<>();
        
        list.add("b");
        list.add("o");
        list.add("r");
        list.add("a");
        
        
        for(int i=0;i<list.size();i++)
            System.out.println(list.get(i));
        System.out.println();
        
        list.remove(0);
        
        for(int i=0;i<list.size();i++)
            System.out.println(list.get(i));
        System.out.println();
        
        
        for(String s : list)
            System.out.println(s);
        System.out.println();
        
        Iterator<String> lit = list.iterator();
        while(lit.hasNext())
            System.out.println(lit.next());
        System.out.println();
        
    }
 
}
/////////////////////////////////////////////
 
package test;
 
import java.util.*;
 
class Car implements Comparable<Car> {
    private int disp;
 
    public Car(int d) {
        disp = d;
    }
 
    @Override
    public String toString() {
        return "" + disp;
    }
 
    @Override
    public int compareTo(Car o) {
        return disp - o.disp;
    }
}
 
public class CarSortCollections {
 
    public static void main(String[] args) {
 
        List<Car> list = new LinkedList<>();
        list.add(new Car(1200));
        list.add(new Car(400));
        list.add(new Car(120));
 
        Collections.sort(list);
 
        for (Iterator<Car> itr = list.iterator(); itr.hasNext();)
            System.out.println(itr.next().toString());
    }
}
 
/////////////////////////////
package test;
 
import java.util.HashSet;
import java.util.Objects;
 
class Person{
    private String name;
    private int age;
    public Person(String name, int age) {
        this.name=name;
        this.age=age;
    }
    public String toString() {
        return name+"("+age+"세)";
    }
    
    @Override
    public int hashCode() {
        return Objects.hash(name,age);
    }
    @Override
    public boolean equals(Object obj) {
        Person comp=(Person)obj;
        if(comp.name.equals(name)&&(comp.age==age))
            return true;
        else
            return false;
    }
    
}
 
public class HashEquals {
 
    public static void main(String[] args) {
        HashSet<Person> hset = new HashSet<>();
        hset.add(new Person("k",20));
        hset.add(new Person("J",20));
        hset.add(new Person("M",20));
        hset.add(new Person("k",20));
        
        System.out.println(hset.size());
        System.out.println(hset);
    }
 
}
//////////////////////////
package test;
import java.util.*;
 
 
class HashMapColl{
    public static void main(String[] args) {
        HashMap<Integer,String> map = new HashMap<>();
        
        map.put(12,"bora");
        map.put(22,"bowrwea");
        map.put(11,"b2343ra");
        
        System.out.println(map.get(12));
        
        map.remove(22);
        
        System.out.println("11번:"+map.get(11));
        
        Set<Integer> ks =map.keySet();
        for(Iterator<Integer> itr = ks.iterator();itr.hasNext();)
            System.out.println(map.get(itr.next()));
        System.out.println();
    }
 
}
////////////////////////////
package test;
 
import java.util.HashSet;
 
class Num{
    private int num;
    public Num(int n) {num=n;}
    
    @Override
    public String toString() {
        return String.valueOf(num);
    }
    @Override
    public int hashCode() {
        return num%3;
    }
    @Override
    public boolean equals(Object obj) {
        if(num ==((Num)obj).num)
            return true;
        else
            return false;
        
    }
}
public class HashSetEquality {
 
    public static void main(String[] args) {
        HashSet<Num> set = new HashSet<>();
        set.add(new Num(7799));
        set.add(new Num(7799));
        set.add(new Num(9955));
        System.out.println(set.size());
        
        for(Num n : set)
            System.out.println(n.toString());
    }
 
}