package Pak01;

public class TestString {

public static void main(String[] args) { 

     String a="faADsf";

    for(int i=0;i<a.length();i++) {

                //判斷是否是大寫字母

                if(Character.isUpperCase(a.charAt(i))){

                        //將大寫字母變成小寫輸出

     System.out.print(Character.toLowerCase(a.charAt(i)));

    }

                //判斷是否是小寫字母    

    if(Character.isLowerCase(a.charAt(i))){

                        //將小寫字母變成大寫輸出

     System.out.print(Character.toUpperCase(a.charAt(i)));   

            }   

            }    

        }

}