题解 | #按照格式输入并交换输出#

import java.util.Scanner;
public class Main {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        String twoNums = in.nextLine();
        String[] nums = twoNums.split(",");//将a,b分隔开
        System.out.println(nums[0].substring(0,2) + nums[1].substring(2) + "," + nums[1].substring(0,2) + nums[0].substring(2));//利用子字符串直接输出
    }
}