public static void main(String[] args) { System.out.println("接收用户输入一个月份和一个日期,计算出是一年当中的第几天"); System.out.println("\t输入月份后,按下回车,在输入日期"); System.out.println("\n请输入4位年数字"); while (true) { int x; int day = 0; int cal = 0; Scanner scanner = new Scanner(System.in); int year = scanner.nextInt(); boolean leapYear = isLeapYear(year); System.out.println("请输入月份:"); int month = scanner.nextInt(); // 闰年2月29天 if (month == 2 && leapYear) { System.out.println("请输入日期:"); day = scanner.nextInt(); while (day > 29 || day < 1) { System.out.println("输入有误,重新输入日期:"); x = scanner.nextInt(); day = x; } } // 平年2月28天 if (month == 2 && !leapYear) { System.out.println("请输入日期:"); day = scanner.nextInt(); while (day > 28 || day < 1) { System.out.println("输入有误,重新输入日期:"); x = scanner.nextInt(); day = x; } } if (month % 2 != 0) { System.out.println("请输入日期:"); day = scanner.nextInt(); while (day > 31 || day < 1) { System.out.println("输入有误,重新输入日期:"); x = scanner.nextInt(); day = x; } } if (month != 2 && month % 2 == 0) { System.out.println("请输入日期:"); day = scanner.nextInt(); while (day > 30 || day < 1) { System.out.println("输入有误,重新输入日期:"); x = scanner.nextInt(); day = x; } } System.out.println("你输入的是:" + year + "年" + month + "月" + day + "日"); cal = getDays(year, month, day); System.out.println(year + "年" + month + "月" + day + "日, 是" + year + "中第" + cal + "天"); } } /** * 判断是否是闰年 * 能被4整除且不能被100整除,或者 能被400整除 * @param year * @return */ public static boolean isLeapYear(int year) { boolean leapYear = false; if (year % 4 == 0 && year % 100 != 0 || year % 400 == 0) { leapYear = true; } return leapYear; } /** * 根据年,月,日,计算总天数 * @param year * @param month * @return */ public static int getDays(int year, int month, int day) { int arr[] = {31, 28, 31, 30, 31, 30, 31, 30, 31, 30, 31, 30}; boolean leapYear = isLeapYear(year); if (leapYear) { arr[1] = 29; } int sum = 0; for (int i = 0; i < month -1; i++) { sum += arr[i]; } sum = sum + day; return sum; }
代码逻辑:
(1)判断输入的年份是否是闰年,判断标准:能被4整除且不能被100整除 或者 能被400整除
(2)月份检查,分为4中情况
a.闰年且为2月,此时2月有29天
b.平年且为2月,此时2月有28天
c.平年,能被2整除,此时月份有30天
d.平年,不能被2整除,此时月份有31天
(3)计算天数,初始化一个平年的月份天数数组,如果为闰年,则更改数组中2月的天数,循环累加天数