Problem:
Toggling Cases

Write a program which converts uppercase/lowercase letters to lowercase/uppercase for a given string.

Input

A string is given in a line.

Output

Print the converted string in a line. Note that you do not need to convert any characters other than alphabetical letters.

Constraints

The length of the input string < 1200

Sample Input

fAIR, LATER, OCCASIONALLY CLOUDY.

Sample Output

Fair, later, occasionally cloudy.

Solution in JAVA (judge verdict: Accepted)

import java.util.Scanner;
public class Main {
    public static void main(String[] args) {
        // 標準入力からデータを読み込む準備
        try (Scanner sc = new Scanner(System.in)) {
            String line = sc.nextLine();
            String answer = "";
            int length = line.length();
            
            for (int i = 0; i < length; i++) {
                char ch = line.charAt(i); // 文字列(line)からi番目の文字を取り出す
                // Character.isLowerCase で小文字かどうか判断可能
                if( Character.isLowerCase(ch)){
                    ch = Character.toUpperCase(ch);
                }else{
                    ch = Character.toLowerCase(ch);
                }
                answer += String.valueOf(ch);
                // Character.toUpperCase, Character.toLowerCase で変換
                // 記号は上記メソッドで変換にかけても変化しない
            }
            System.out.println(answer);
        }
    }
}