[英]How to get the date from user input in Java?
I need to print a calendar from the input date given by the user.我需要从用户给出的输入日期打印日历。 HOWEVER, I AM NOT ALLOWED TO USE ANY PREDEFINED DATE CLASS.
但是,我不允许使用任何预定义的日期 CLASS。
Currently, I am able to print the month and the year, however, I can't seem to figure out how to print day in which that date falls on in the particular month + year.目前,我可以打印月份和年份,但是,我似乎无法弄清楚如何打印该日期在特定月份 + 年份中的日期。 I am very new to Java so any help would be greatly appreciated!
我对 Java 非常陌生,因此将不胜感激任何帮助!
Here is an example of the desired output:以下是所需 output 的示例:
24/05/2020 is a Sunday and locates in the fourth week of May 2020
The calendar of May 2020 is:
MON TUE WED THU FRI SAT SUN
1 2 3
4 5 6 7 8 9 10
11 12 13 14 15 16 17
18 19 20 21 22 23 24
25 26 27 28 29 30 31
Here is my output so far:到目前为止,这是我的 output:
22/5/2020 is a null and located in May
Here is the calendar for May:
May 2020
-----------------------------
Sun Mon Tue Wed Thu Fri Sat
1 2
3 4 5 6 7 8 9
10 11 12 13 14 15 16
17 18 19 20 21 22 23
24 25 26 27 28 29 30
31
Here is what I have tried so far:这是我到目前为止所尝试的:
import java.util.Scanner;
public class PrintCalendar {
/** Main method */
public static void main(String[] args) {
// Prompt the user to enter year
Scanner scanner = new Scanner(System.in);
// Prompt the user to enter year
System.out.print("Enter year (e.g.1999): ");
int year = scanner.nextInt();
// Prompt the user to enter month
System.out.print("Enter month (1-12): ");
int month = scanner.nextInt();
System.out.println("Enter the day (1-7): ");
int theDay = scanner.nextInt();
// Print calendar for the month of the year
printMonth(year, month, theDay);
}
/** Print the calendar for a month in a year */
static void printMonth(int year, int month, int day) {
// Print the headings of the calendar
printMonthTitle(year, month, day);
// Print the body of the calendar
printMonthBody(year, month);
}
/** Print the month title, e.g., May, 1999 */
static void printMonthTitle(int year, int month, int day) {
System.out.println(day + "/"+ month + "/" + year + " is a " + getDayOfWeek(day) + " and located in " + getMonthName(month));
System.out.println();
System.out.println("Here is the calendar for " + getMonthName(month) + ": ");
System.out.println();
System.out.println(" " + getMonthName(month)
+ " " + year);
System.out.println("-----------------------------");
System.out.println(" Sun Mon Tue Wed Thu Fri Sat");
}
/** Get the English name for the month */
static String getMonthName(int month) {
String monthName = null;
switch (month) {
case 1: monthName = "January"; break;
case 2: monthName = "February"; break;
case 3: monthName = "March"; break;
case 4: monthName = "April"; break;
case 5: monthName = "May"; break;
case 6: monthName = "June"; break;
case 7: monthName = "July"; break;
case 8: monthName = "August"; break;
case 9: monthName = "September"; break;
case 10: monthName = "October"; break;
case 11: monthName = "November"; break;
case 12: monthName = "December";
}
return monthName;
}
public static String getDayOfWeek(int day) {
String dayName = null;
switch (day) {
case 1: dayName = "Sunday"; break;
case 2: dayName = "Monday"; break;
case 3: dayName = "Tuesday"; break;
case 4: dayName = "Wednesday"; break;
case 5: dayName = "Thursday"; break;
case 6: dayName = "Friday"; break;
case 7: dayName = "Saturday";
}
return dayName;
}
/** Print month body */
static void printMonthBody(int year, int month) {
// Get start day of the week for the first date in the month
int startDay = getStartDay(year, month);
// Get number of days in the month
int numberOfDaysInMonth = getNumberOfDaysInMonth(year, month);
// Pad space before the first day of the month
int i = 0;
for (i = 0; i < startDay; i++)
System.out.print(" ");
for (i = 1; i <= numberOfDaysInMonth; i++) {
if (i < 10)
System.out.print(" " + i);
else
System.out.print(" " + i);
if ((i + startDay) % 7 == 0)
System.out.println();
}
System.out.println();
}
/** Get the start day of the first day in a month */
static int getStartDay(int year, int month) {
// Get total number of days since 1/1/1800
int startDay1800 = 3;
int totalNumberOfDays = getTotalNumberOfDays(year, month);
// Return the start day
return (totalNumberOfDays + startDay1800) % 7;
}
/** Get the total number of days since January 1, 1800 */
static int getTotalNumberOfDays(int year, int month) {
int total = 0;
// Get the total days from 1800 to year - 1
for (int i = 1800; i < year; i++)
if (isLeapYear(i))
total = total + 366;
else
total = total + 365;
// Add days from Jan to the month prior to the calendar month
for (int i = 1; i < month; i++)
total = total + getNumberOfDaysInMonth(year, i);
return total;
}
/** Get the number of days in a month */
static int getNumberOfDaysInMonth(int year, int month) {
if (month == 1 || month == 3 || month == 5 || month == 7 ||
month == 8 || month == 10 || month == 12)
return 31;
if (month == 4 || month == 6 || month == 9 || month == 11)
return 30;
if (month == 2) return isLeapYear(year) ? 29 : 28;
return 0; // If month is incorrect
}
/** Determine if it is a leap year */
static boolean isLeapYear(int year) {
return year % 400 == 0 || (year % 4 == 0 && year % 100 != 0);
}
}
To get day of week you can use your getStartDay()
function which will return you the start day of the month using this we can do (day + startDay) % 7
which will give us the day for the current date.要获取星期几,您可以使用您的
getStartDay()
function ,这将使用我们可以执行的(day + startDay) % 7
返回您当月的开始日期,这将为我们提供当前日期的日期。
Here are some changes you need to make:以下是您需要进行的一些更改:
Print statement :打印声明:
System.out.println(day + "/" + month + "/" + year + " is a " + getDayOfWeek(day, year, month) + " and located in " + getMonthName(month));
Your Function :您的 Function :
//pass year and month as well
public static String getDayOfWeek(int day, int year, int month) {
String dayName = null;
//getting start day of month
int startDay = getStartDay(year, month);//call function
int days = (day + startDay) % 7;
//if days will be 0 means start month from monday and leap year
if (days == 0) {
//add 1 to day
days = day + 1;
} else {
//use same days
days = days;
}
switch (days) {
case 1:
dayName = "Sunday";
break;
case 2:
dayName = "Monday";
break;
case 3:
dayName = "Tuesday";
break;
case 4:
dayName = "Wednesday";
break;
case 5:
dayName = "Thursday";
break;
case 6:
dayName = "Friday";
break;
case 7:
dayName = "Saturday";
}
return dayName;
}
Output : Output :
if you use LocalDate, you can find the day name like this如果您使用 LocalDate,您可以找到这样的日期名称
import java.time.LocalDate;
public static String getDay(int month, int day, int year) {
return LocalDate.of(year, month, day).getDayOfWeek().name();
}
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