[코테] 2. 대소문자 변환

import java.util.*;

class Main{
 public char[] solution(char[] arr){
 for(int i=0;i<arr.length;i++){
    if(arr[i]>=65 && arr[i]<=90) arr[i] =(char)(arr[i]+32);
    else  arr[i] =(char)(arr[i]-32);
 
  }
  return arr;
 }

 public static void main(String[] args){
 Main T = new Main(); 
 Scanner kb = new Scanner(System.in);
 String input = kb.next();
 char[] arr = input.toCharArray();
 System.out.println(T.solution(arr));
 }
}

import java.util.*;

class Main{
   public String solution(String str){
     String answer="";
     for(char x: str.toCharArray()){
       if(Character.isLowerCase(x)) answer+=Character.toUpperCase(x);
       else answer+=Character.toLowerCase(x);
     
     }
     return answer;
   }
   public static void main(String[] args){
    Main T = new Main();
    Scanner kb = new Scanner(System.in);
    String str = kb.next();
    System.out.prinltn(T.solution(str));
   }

}