JAVA Level 7

1~5. 다음 코드에 대한 출력 결과를 쓰시오.

 

1.

import java.util.ArrayList;

public class Main {
    public static void main(String[] args) {
        ArrayList<Integer> list = new ArrayList<>();
        list.add(1);
        list.add(2);
        list.add(3);
        System.out.println(list.size());
    }
}

 

2.

import java.util.LinkedList;

public class Main {
    public static void main(String[] args) {
        LinkedList<String> list = new LinkedList<>();
        list.add("A");
        list.add("B");
        list.add("C");
        System.out.println(list.get(1));
    }
}

 

3.

import java.util.HashMap;

public class Main {
    public static void main(String[] args) {
        HashMap<String, Integer> map = new HashMap<>();
        map.put("One", 1);
        map.put("Two", 2);
        map.put("Three", 3);
        System.out.println(map.get("Two"));
    }
}

 

4.

import java.util.HashSet;

public class Main {
    public static void main(String[] args) {
        HashSet<String> set = new HashSet<>();
        set.add("A");
        set.add("B");
        set.add("C");
        System.out.println(set.contains("B"));
    }
}

 

5.

import java.util.ArrayList;
import java.util.Iterator;

public class Main {
    public static void main(String[] args) {
        ArrayList<Integer> list = new ArrayList<>();
        list.add(10);
        list.add(20);
        list.add(30);
        Iterator<Integer> it = list.iterator();
        while (it.hasNext()) {
            System.out.println(it.next());
        }
    }
}

 

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정답
(드래그 시 정답이 보입니다.)

1. 3
2. B
3. 2
4. true
5. 10

20

30