?public static void amam(String[] args){? ? Scanner scan = new Scanner(System.in);? ? System.out.println("請輸入一個年份值:");? ? int year = scan.nextInt();? ? System.out.println("請輸入一個月份值:");? ? int month = scan.nextInt();? ? //判斷輸入合法性? ? System.out.println("請輸入一個天:");? ? int day = scan.nextInt();? ? //判斷合法性? ? day--;? ? if(day < 1){? ? day = 31;? ? if(month == 5 || month == 7 || month == 10 || month == 12){? ? day = 30;? ? }else if(month == 3){? ? day = (year % 400 == 0 || (year % 4 == 0 && year % 100 !=0))?29:28;? ? }if(month == 1){? ? year--;? ? month = 12;? ? }else{? ? month--;? ? }? ? }? ? System.out.println(year+"年"+month+"月"+day+"日");? ? }能解釋下整個代碼的意思嗎？尤其是這段：if(month == 5 || month == 7 || month == 10 || month == 12)