变更大小写字母1

import java.util.Scanner;
public class H4{
    public static void main(String[] args) {
        Scanner scan = new Scanner(System.in);
        System.out.println("请输入一个字符");
        char ch = scan.next().charAt(0);//97~122   65~90
        if(ch>=‘a‘&&ch<=‘z‘){//小写字母
            ch -= 32;
        }else if(ch>=‘A‘&&ch<=‘Z‘){
            ch += 32;
        }
        System.out.println(ch);
    }
}