BOJ2744 대소문자 바꾸기

https://www.acmicpc.net/problem/2744

2744번: 대소문자 바꾸기

 

import java.util.*;
import java.io.*;
public class Main
{
	public static void main(String[] args) throws IOException{

	    
	    BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
	    String word = br.readLine();
        StringBuffer sb = new StringBuffer();
	    for(int i =0; i<word.length(); i++){
	        if('A'<= word.charAt(i) && word.charAt(i)<='Z'){
	            sb.append((char)(word.charAt(i)-'A'+'a'));
	        }else{
	            sb.append((char)(word.charAt(i)-'a'+'A'));
	        }
	    }
	    System.out.println(sb.toString());
		
	}
}