java 编写一个程序，提示用户输入年和月（前 3 个字母，第一个字母大写）然后显示该月的天数
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原文地址: http://stackoverflow.com/questions/28551502/
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Write a program that prompts the user to enter a year and a month (first 3 letters, first letter uppercase) then displays the days of the month
提问by Chris Redfieldea
Write a program that prompts the user to enter a year and the first three letters of a month name (with the first letter in uppercase) and displays the number of days in the month. Here is a sample run:
编写一个程序，提示用户输入年份和月份名称的前三个字母（首字母大写）并显示该月的天数。这是一个示例运行：
Enter a year: 2001
输入年份：2001
Enter a month: Jan
输入月份：Jan
"Jan 2001 has 31 days"
“2001 年 1 月有 31 天”
Enter a year: 2016
输入年份：2016
Enter a month: Feb
输入月份：二月
"Jan 2016 has 29 days" (I do not understand this one specifically) My issue is with the Leap Year portion. I don't understand how to work it in with the rest of the program because the number of days are supposed to change. Nor do I understand why the month of "Feb" changed to "Jan" in the example. I need help reworking my program. All I can use is what is seen in the code below: """If statements and switch/case."""
“2016 年 1 月有 29 天”（我不具体理解这一天）我的问题是闰年部分。我不明白如何与程序的其余部分一起工作，因为天数应该改变。我也不明白为什么在这个例子中“二月”变成了“一月”。我需要帮助修改我的程序。我所能使用的只是下面代码中的内容："""If 语句和 switch/case。"""
import java.util.Scanner;
public class NewClass {
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
System.out.print("Enter a year: ");
int year = input.nextInt();
input.nextLine();
System.out.print("Enter a month: ");
String month = input.nextLine();
// Taken from the book per request of the instructor
boolean isLeapYear = ((year % 4 == 0 && year % 100 != 0) || (year % 400 == 0));
switch (month){
case "Jan":
case "Mar":
case "May":
case "July":
case "Aug":
case "Oct":
case "Dec":
System.out.println(month + " " + year + " has 31 days"); break;
case "Apr":
case "Jun":
case "Sep":
case "Nov":
System.out.println(month + " " + year + " has 30 days"); break;
case "Feb":
System.out.println(month + " " + year + " has 28 days");
}
}
}
I'd appreciate some help or any form of offering at this point. My instructor is away for the week which leaves me in complete darkness, without proper guidance.
在这一点上，我很感激一些帮助或任何形式的提供。我的导师离开了一周，这让我完全处于黑暗之中，没有适当的指导。
采纳答案by Saul Hamadani
I ran your program. I don't exactly know why you were getting that error about Feb 2016 resulting in Jan 2016 results. When I ran it, it ran exactly how it should. However, you did not return the correct amount of days in February when a leap year occurs. You wrote out the correct equation to determine a leap year, but you didn't use it.
我运行了你的程序。我不完全知道为什么您会在 2016 年 2 月出现该错误，从而导致 2016 年 1 月的结果。当我运行它时，它完全按照它应该的方式运行。但是，当闰年发生时，您没有返回 2 月份的正确天数。你写出了确定闰年的正确方程，但你没有使用它。
case "Sep":
case "Nov":
System.out.println(month + " " + year + " has 30 days"); break;
case "Feb":
if(isLeapYear)
{
System.out.println(month + " " + year + " has 29 days");
}
else
{
System.out.println(month + " " + year + " has 28 days");}
}
