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How do i get my new value to go back through the if statements

I'm trying to get the amount of days until the meeting to go back and print out the day the new meeting is on but I keep getting an integer instead of the string.
import java.util.Scanner;
public class NextMeeting {
public static void main(String [] args) {
int day, daysToMeeting = 0;
Scanner scan = new Scanner(System.in);
System.out.println("Enter the day of the week 0-6: ");
day = scan.nextInt();
System.out.println("Enter the days to meeting: ");
daysToMeeting = scan.nextInt();
if (day == 0) {
System.out.println("Today is Sunday");
} else if (day == 1) {
System.out.println("Today is Monday");
}
else if (day == 2) {
System.out.println("Today is Tuesday");
}
else if (day == 3) {
System.out.println("Today is Wednesday");
}
else if (day == 4) {
System.out.println("Today is Thursday");
}
else if (day == 5) {
System.out.println("Today is Friday");
}
else if (day == 6) {
System.out.println("Today is Saturday");
}
System.out.println("Today is: " + day);
if( daysToMeeting >= 6) {
day = daysToMeeting - 7;
}
else {
day = day + 6;
}
System.out.println("Days to the meeting is " + daysToMeeting + " +days.");
System.out.println("Meeting day is : " + Integer.toString(day));
}
}
The output for days is still 3 but we need to get it to print out Wednesday. I don't know how to make that happen.

You can use DayOfWeek enum.
System.out.println("Meeting day is : " + DayOfWeek.of(day).toString());
You can also remove nested if-else statement and use DayOfWeek enum to display "Today is xyz-day".

You are printing out integers because day is an int. It may be inefficient but an easy fix is to create a String variable and in another if-statement block below the daysToMeeting if-else block, assign the String to each corresponding integer, such as
String meetingDay;
if(day == 1){
meetingDay = "Monday";
}
and then print out using the String variable.
System.out.println("Meeting day is : " + meetingDay);

Just create a method which will return the day of week String by passing the day int. Then print the result.
public String intToDayName(int day) {
if(day > 6) {
day = day % 7;
}
if (day == 0) {
return "Sunday";
} else if (day == 1) {
return "Monday";
}
else if (day == 2) {
return "Tuesday";
}
else if (day == 3) {
return "Wednesday";
}
else if (day == 4) {
return "Thursday";
}
else if (day == 5) {
return "Friday";
}
else if (day == 6) {
return "Saturday";
}
return "Error";
}
calling it in your prints:
System.out.println("Meeting day is : " + intToDayName(daysToMeeting));
System.out.println("Today is " + intToDayName(day));
If you actually want your code to go back and print the first if-else statements then I suggest looping.

Why doesn't my date validation code work?

my code doesn't return any value and i have no idea why. My assignment requires me to write a code that accepts date in mm/dd/yyyy format and im required to put leap year in. The problem is, i dont get back any input. Im an amateur ad i dont know what is wrong. Im also allowed to use Case statment but I'm not sure how to implement case.
import java.util.Scanner;
public class Question1 {
public static void main(String[] args) {
Scanner sc = new Scanner(System.in).useDelimiter("/");
System.out.println("Please enter a date in mm/dd/yyyy format: ");
String mm = sc.next();
String dd = sc.next();
String yyyy = sc.next();
int month = Integer.parseInt(mm);
int day = Integer.parseInt(dd);
int year = Integer.parseInt(yyyy);
if (month <= 0 || month>12)
{
System.out.println("invalid month ");
}
if (year%4 != 0 || month == 02 || day >= 29)
{
System.out.println("invalid date");
}
if (month == 4 || month == 6 || month == 9 || month == 11 || day >= 31)
{
System.out.println("Invalid day");
}
if (month == 1 || month == 3 || month == 5 || month == 7 || month == 8 || month == 10 || month == 12 || day >=32 )
{
System.out.println("Invalid day");
}
else
{
System.out.println("Valid date");
}
}
}

The code sets the delimiter to /. Then you enter something like 12/25/2016. The first sc.next() call gets the 12. The second one gets the 25. The third... waits, because it doesn't see another / so it doesn't know you're done. If you typed 12/25/2016/ with your current code, it would at least give output, even if that output isn't correct yet.

you want to use switch case then go through the below code:
import java.util.Scanner;
public class Question1 {
public static void main(String[] args) {
Scanner sc = new Scanner(System.in).useDelimiter("/");
System.out.println("Please enter a date in mm/dd/yyyy/ format: ");
String mm = sc.next();
String dd = sc.next();
String yyyy = sc.next();
int month = Integer.parseInt(mm);
int day = Integer.parseInt(dd);
int year = Integer.parseInt(yyyy);
boolean valid = isValidDate(day,month,year);
if (valid == true)
{
System.out.println("Date is Valid");
}
else
{
System.out.println("Date is InValid");
}
}
public static boolean isValidDate(int day, int month ,int year)
{
boolean monthOk = (month >= 1) && (month <= 12);
boolean dayOk = (day >= 1) && (day <= daysInMonth(year, month));
return (monthOk && dayOk);
}
private static int daysInMonth(int year, int month) {
int daysInMonth;
switch (month) {
case 1:
case 3:
case 5:
case 7:
case 8:
case 10: // go through
case 12:
daysInMonth = 31;
break;
case 2:
if (((year % 4 == 0) && (year % 100 != 0)) || (year % 400 == 0)) {
daysInMonth = 29;
} else {
daysInMonth = 28;
}
break;
default:
// returns 30 even for nonexistant months
daysInMonth = 30;
}
return daysInMonth;
}
}
take input as 12/25/2016/, not this 12/25/2016.

Here is something to get you started:
final String DELIMITER = "/";
Scanner sc = new Scanner(System.in);
System.out.println("Please enter a date in mm/dd/yyyy format:\n ");
String date = sc.next();
sc.close();
String[] dateParts = date.split(DELIMITER);
//check : if dateParts size is not 3 ....something is wrong
String mm = dateParts[0];
String dd = dateParts[1];
String yyyy = dateParts[2];
System.out.println(mm+" "+ dd +" "+ yyyy);

It seems you have put else in wrong place. Suppose you second condition is getting correct and all other false, then also your program will show it as valid date and same on the opposite side.
For example, say day is 30 for any date, then it will satisfy second condition and it will show you "Invalid date".
You should write if else as follows.
If{
If{
If{
}
}
}else{
}
All if must be in a nested if and then else. Your if else sequence is wrong.

JAVA Find day of the week from user entered date [duplicate]

This question already has answers here:
java get day of week is not accurate
(3 answers)
Closed 6 years ago.
I have this code which is built to find day of the week when user enters date but currently it's not working as expected.
Also, I need to help with setting up loop to ask question again and again until user press "Control + Z" to exit.
Can anyone check and point me out issues. Also help with loop.
import java.util.Calendar;
import java.util.Scanner;
public class CalendarProject {
#SuppressWarnings({ "resource" })
public static void main(String[] args) {
Calendar c = Calendar.getInstance();
Scanner input = new Scanner (System.in);
//Enter the Day
System.out.println("Enter the day in number:");
int day1= input.nextInt( );
//Enter the Month
System.out.println("Enter the Month in number");
int month= input.nextInt( );
//Enter the Year
System.out.println("Enter the Year in number format");
int year= input.nextInt( );
//Display the day
int dayOfWeek = c.get(Calendar.DAY_OF_WEEK);
System.out.println(String.format("%d/%d/%d",day1,month,year));
System.out.println(c.get(Calendar.DAY_OF_WEEK));
if (dayOfWeek == Calendar.SUNDAY) {
System.out.println("Sunday");
}
else if (dayOfWeek == Calendar.MONDAY) {
System.out.println("Monday");
}
else if (dayOfWeek == Calendar.TUESDAY) {
System.out.println("Tuesday");
}
else if (dayOfWeek == Calendar.WEDNESDAY) {
System.out.println("Wednesday");
}
else if (dayOfWeek == Calendar.THURSDAY) {
System.out.println("Thursday");
}
else if (dayOfWeek == Calendar.FRIDAY) {
System.out.println("Friday");
}
else if (dayOfWeek == Calendar.SATURDAY) {
System.out.println("Saturday");
}
}
}

1.You never set the input date in Calender object,hence it will never work as desired. So you need to use c.setTime(date); Here date is Date object.
2. For loop, you can use do while loop to ask user again and again.
Following is your modified code
public static void main(String[] args) {
Calendar c;
SimpleDateFormat formatter = new SimpleDateFormat("dd/MM/yyyy");
Scanner input = new Scanner (System.in);
try {
do{
System.out.println("Enter the day in number:");
int day1= input.nextInt();
//Enter the Month
System.out.println("Enter the Month in number");
int month= input.nextInt( );
//Enter the Year
System.out.println("Enter the Year in number format");
int year= input.nextInt( );
Date date = formatter.parse((String.format("%d/%d/%d",day1,month,year)));
System.out.println(date);
c= Calendar.getInstance();
c.setTime(date);
int day = c.get(Calendar.DAY_OF_WEEK);
if (day == Calendar.SUNDAY) {
System.out.println("Sunday");
}
else if (day == Calendar.MONDAY) {
System.out.println("Monday");
}
else if (day == Calendar.TUESDAY) {
System.out.println("Tuesday");
}
else if (day == Calendar.WEDNESDAY) {
System.out.println("Wednesday");
}
else if (day == Calendar.THURSDAY) {
System.out.println("Thursday");
}
else if (day == Calendar.FRIDAY) {
System.out.println("Friday");
}
else if (day == Calendar.SATURDAY) {
System.out.println("Saturday");
}
System.out.println("To exit press CTRL+Z(Windows) or CTRL+D(LINUX), or any key to continue");
input.nextLine();
}while (input.hasNextLine());
}catch(NoSuchElementException n){
System.out.println("NoSuchElementException");
}catch(ParseException pe){
System.out.println("invalid date");
}finally {
input.close();
System.out.println("exiting");
}
}
3. If you are using Java 8, you can get rid of all if else blocks by using java.time.DayOfWeek Enum. Just replace all your if else by following lines
DayOfWeek dayOfWeek = DayOfWeek.of((day+6)%7==0?7:(day+6)%7);
System.out.println(dayOfWeek);
I used ternary operator because DayOfWeek takes MONDAY as value of index 1 and Calender.DAY_OF_WEEk takes SUNDAY as value of index 1

How to incorporate error message in the program below?

I'm an beginner IT11 student and we're supposed to make a program that will read in the number of the day, the month, and the year a person was born.
For example, someone born on September 3, 1982, would enter the numbers
3, 9, and 1982
into three separate JOP.showInputDialogs.
If an incorrect value is entered, the program should give a very specific error message explaining why it is invalid and ask the user to enter the information again. A user should never have to reenter more than one of the values when an invalid entry is made (example, if the day is invalid, the user should only have to reenter the day, not the month or the year).
The program will then tell the person their birthdate with the following format:
You were born September 3, 1982.
The format of the date must be as shown above.
Important
- The program MUST do error checking for invalid months (valid between 1 and 12)
- The program MUST do error checking for invalid years (valid >= 1800)
- The program MUST do error checking for invalid day of month (valid between 1 and maxDay in month (30, 31, 28 or 29))
- The program MUST only allow Feb 29 on LEAP YEARS only.
The part I'm stuck on is incorporating an error message for invalid dates. For example, if I were to input April 31, the program should return an error message saying "April only has 30 days", etc. How do I do that? Here is what I've got so far.
import javax.swing.*;
public class A6DateProgram {
public static void main(String[] args) {
int year = getYearFromUser(); //gets user input for year
int month = getMonthFromUser(); //gets user input for month
int day = getDateFromUser(month, year); //gets user input for date
//tells the user their birthdate
System.out.println("You were born " + Months(month) + " " + day + ", "+ year + " " + ".");
} //main
//asks user for year
public static int getYearFromUser(){
String year; //asks user for year
int year1 = 0;
String errorMessage = "";
boolean isLeap = false;
do{
year = JOptionPane.showInputDialog(errorMessage + "Please enter the year you were born in. (>1800)");
if (year == null) {
System.out.println("You clicked cancel");
System.exit(0);
}
// parse string to an int
try {
year1 = Integer.parseInt(year); //parses recieved number to an int
} catch (Exception e) {
errorMessage = "Invalid integer\n"; //if user does not input valid integer
continue; //continues to condition [while(true);]
} // catch
isLeap = validateYear(year1);
if(year1 < 1800 || year1 > 2400){ //number limitation
errorMessage = "Your number must be greater than 1800 or less than 2400. \n"; //if user does not input a valid integer between limit
continue; //continues to condition [while(true);]
}
break;
} while(true);
return year1;
} //getYearFromUser
public static boolean validateYear(int year){
return (year % 400 == 0 ) ? true : (year%100 == 0)? false : (year % 4 == 0)? true: false;
}
//asks user for month
public static int getMonthFromUser(){
String month;
int num = 0;
String errorMessage = "";
do{
month = JOptionPane.showInputDialog(errorMessage + "Please enter the month you were born in as a valid integer. (ex. January = 1)");
if (month == null) {
System.out.println("You clicked cancel");
System.exit(0);
}
// parse string to an int
try {
num = Integer.parseInt(month);
} catch (Exception e) {
errorMessage = "Invalid integer\n";
continue; //continues to condition [while(true);]
} // catch
if(num > 12 || num < 1){
errorMessage = "A year only has 12 months. \n";
continue; //continues to condition [while(true);]
}
break;
} while(true);
return num;
} //getMonthFromUser
//asks user for date
public static int getDateFromUser(int month, int year){
String date;
int day = 0;
String errorMessage = "";
boolean ToF = false;
do{
date = JOptionPane.showInputDialog(errorMessage + "Please enter the date you were born in. (1-31)");
//user clicks cancel
if (date == null) {
System.out.println("You clicked cancel");
System.exit(0);
}
// parse string to an int
try {
day = Integer.parseInt(date);
} catch (Exception e) {
errorMessage = "Invalid integer\n";
continue; //continues to condition [while(true);]
} // catch
ToF = validate(year, month, day); //giving boolean ToF a method to validate the day
if(ToF == false){
errorMessage = "The month you input does not have that date. \n";
continue; //continues to condition [while(true);]
}
break;
} while(true); //do
return day;
} //getDateFromUser
public static boolean validate(int year, int month, int day){
switch(month){
case 1:
case 3:
case 5:
case 7:
case 8:
case 10:
case 12:
if(day < 1 || day > 31)
return false;
break;
case 2:
if(year%4 == 0 || (year%400 == 0 && year%100 != 0)){
if (day < 1 || day > 29)
return false;
}else{
if (day < 1 || day > 28)
return false;
}
break;
case 4:
case 6:
case 9:
case 11:
if(day < 1 || day > 30)
return false;
break;
}
return true;
} //validate
//resonse to user input for month
public static String Months(int month) {
switch (month) {
case 1: return "January";
case 2: return "Febrary";
case 3: return "March";
case 4: return "April";
case 5: return "May";
case 6: return "June";
case 7: return "July";
case 8: return "August";
case 9: return "September";
case 10: return "October";
case 11: return "November";
case 12: return "December";
default: return "Invalid";
} // switch
} //Months
} //A6DateProgram Class

Try with SimpleDateFormat()
String date = "3";
String month = "9";
String year = "1980";
SimpleDateFormat sdf1 = new SimpleDateFormat("ddMMyyyy");
SimpleDateFormat sdf2 = new SimpleDateFormat("MMMM dd, yyyy");
Date date1 = sdf1.parse((Integer.parseInt(date)<10?"0"+date:date)+(Integer.parseInt(month)<10?"0"+month:month)+year);
String ansStr = sdf2.format(date1);
System.out.println("You were born "+ansStr);
If you enter an invail date it automatically take the next date.
Eaxmple if the input is 29-02-2014 it will take as 01-03-2014

asking user for another prompt after wrong input in java

so i'm asking the user for a month and a year. month has to be one of the twelve months and year has to be a number and no letters. i'm trying to figure out the best way to make the program say "wrong input, try again" and prompt them for input again. here's the section of code i'm working with for the month section.
public class MonthLength {
public static void main(String[] args) {
int month = 0;
// Prompt the user to enter a month
SimpleIO.prompt("Enter a month name: ");
String userInput = SimpleIO.readLine();
if (userInput.trim().toLowerCase().equals("january")) {
month = 1;
} else if (userInput.trim().toLowerCase().equals("february")) {
month = 2;
} else if (userInput.trim().toLowerCase().equals("march")) {
month = 3;
} else if (userInput.trim().toLowerCase().equals("april")) {
month = 4;
} else if (userInput.trim().toLowerCase().equals("may")) {
month = 5;
} else if (userInput.trim().toLowerCase().equals("june")) {
month = 6;
} else if (userInput.trim().toLowerCase().equals("july")) {
month = 7;
} else if (userInput.trim().toLowerCase().equals("august")) {
month = 8;
} else if (userInput.trim().toLowerCase().equals("september")) {
month = 9;
} else if (userInput.trim().toLowerCase().equals("october")) {
month = 10;
} else if (userInput.trim().toLowerCase().equals("november")) {
month = 11;
} else if (userInput.trim().toLowerCase().equals("december")) {
month = 12;
}
// Terminate program if month is not a proper month name
if (month < 1 || month > 12) {
System.out.println("Illegal month name; try again");
return;
}
and here's what i'm working with for the year section:
// Prompt the user to enter a year
SimpleIO.prompt("Enter a year: ");
userInput = SimpleIO.readLine();
int year = Integer.parseInt(userInput);
//Here, trying to use hasNextInt to make sure input is an integer
//If it's not, need to give an error message and prompt input again
// public boolean hasNextInt()
//Prompt input again if year is negative
if (year < 0) {
System.out.println("Year cannot be negative; try again");
return;
}
// Determine the number of days in the month
int numberOfDays;
switch (month) {
case 2: // February
numberOfDays = 28;
if (year % 4 == 0) {
numberOfDays = 29;
if (year % 100 == 0 && year % 400 != 0)
numberOfDays = 28;
}
break;
case 4: // April
case 6: // June
case 9: // September
case 11: // November
numberOfDays = 30;
break;
default: numberOfDays = 31;
break;
}
// Display the number of days in the month
System.out.println("There are " + numberOfDays +
" days in this month");
}
}
after seeing the code i'm sure it will be more clear what i'm asking. if they enter a word that isn't a month, prompt them and ask for input again. same thing if they enter a year that isn't integers. thanks in advance!

Running it in a loop, will do:
String userInput;
int month;
do{
SimpleIO.prompt("Enter a month name: ");
userInput = SimpleIO.readLine();
try{
month = Integer.parseInt(userInput);
} catch(NumberFormatException e){
continue;
}
}while(month <= 0 || month > 12);

You should create a loop that keeps prompting the user until the month is correctly inserted. Something in the following lines:
boolean correct_month = false; // Control variable
while(!correct_month)
{
int month = 0;
// Prompt the user to enter a month
SimpleIO.prompt("Enter a month name: ");
String userInput = SimpleIO.readLine();
...
// If the month is indeed correct
// then correct_month = true;
}
Then you apply the same idea to the years.
Instead of having all of those conditions on the month, I think it is better to add all the month strings into an ArrayList:
ArrayList <String> all_months = new ArrayList <String> ();
and then you just have to use all_months.indexOf with the string insert by the user. If it returns -1 the string is not a valid month, otherwise, it will give you the position where the month is on the list. For example
month = all_months.indexOf(userInput);
if(month != -1){
correct_month = true;
}
Thus, the complete solution would be something like:
ArrayList <String> all_months = new ArrayList <String> ();
all_months.add("january");
... // and so one
int month = 0; // Control variable
while(month <= 0)
{
// Prompt the user to enter a month
SimpleIO.prompt("Enter a month name: ");
String userInput = SimpleIO.readLine();
month = all_months.indexOf(userInput.trim().toLowerCase()) + 1;
}