[JAVA] 문자열 뒤집기 String reverse

1. StringBuffer 객체 생성 후 reverse() 사용.

String a = "123";

StringBuffer sb = new StringBuffer(str);
String reversed_a = sb.reverse().toString();

 

2. char[]로 변환하여 뒤집기

public class string_reverse {

	public static void main(String[] args) {
		String str = "123";

		char[] arr = str.toCharArray();
		char[] reversed_arr = new char[arr.length];
		for(int i=0; i<arr.length; i++){
			reversed_arr[arr.length-1-i] = arr[i];
		}

		String reversed_str = new String(reversed_arr);
		System.out.println(reversed_str);

	}

}

3. List로 변환 후 Collections.reverse(list) 이용하여 뒤집기

import java.util.List;
import java.util.ArrayList;
import java.util.Collections;
import java.util.ListIterator;

public class string_reverse_bylist {

	public static void main(String[] args) {
		String str = "123";
		
		char[] arr = str.toCharArray();
		List<Character> list = new ArrayList<Character>();
		for(char each : arr) {
			list.add(each);
		}
		Collections.reverse(list);
		
		ListIterator li = list.listIterator();
		while(li.hasNext()) {
			System.out.print(li.next());
		}

	}

}

Collections.reverse(list)

ListIterator

 

 

 

<출처>

[1] https://yangbox.tistory.com/59

[2] https://docs.oracle.com/javase/7/docs/api/