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C# Converting values passed as arguments to variables

I am having trouble understanding the relationship between variables and arguments passed to a method. The program below is supposed to take three integers from the main method (M, D, Y) and use various methods to validate if it is a valid date. This includes ensuring the year is between 1900 and 2100, as well as making sure the month is 1-12, and the day is within that month's range of days (including Feb 29th on leap years). If the date from the main method is not valid, the program should say so and print the default date of 1/1/1900. The code below always prints the default no matter what arguments are provided. I believe that this is because there is an issue with how I am using either the variables M, D, Y or the variables Month, Day, Year. This program is for an assignment in which I have to use all methods and constructors in the code below. I am unsure how to have the arguments M, D, Y get turned into the variables Month, Day, and Year, so they can be printed by the ShowDate method which was provided for me.
class Date
{
private int Month;
private int Day;
private int Year;
// Sets date to 1/1/1900
public Date()
{
Month = 1;
Day = 1;
Year = 1900;
}
public Date(int M, int D, int Y)
{
SetDate(M, D, Y);
}
public Boolean SetDate(int M, int D, int Y)
{
if (ValidateDate(M, D, Y))
{
Month = M;
Day = D;
Year = Y;
return true;
}
else
{
Console.WriteLine("Invalide date");
SetDefaultDate();
return false;
}
}
private void SetDefaultDate()
{
Month = 1;
Day = 1;
Year = 1900;
}
// Determines if date is valid.
public Boolean ValidateDate(int M, int D, int Y)
{
ValidateMonth();
ValidateDay();
ValidateYear();
if (ValidateMonth() && ValidateDay() && ValidateYear())
{
ShowDate();
return true;
}
else
{
return false;
}
}
// Determines if month is valid.
public Boolean ValidateMonth()
{
if (Month >= 1 && Month <= 12)
{
return true;
}
else
{
return false;
}
}
// Determines if year is valid.
public Boolean ValidateYear()
{
if(Year >= 1900 && Year <= 2100)
{
return true;
}
else
{
return false;
}
}
// Determines if day is valid
public Boolean ValidateDay()
{
IsLeapYear();
if(Month == 1 || Month == 3 || Month == 5 || Month == 7 || Month == 8 || Month == 10 || Month == 12)
{
if (Day >= 1 && Day <= 31)
{
return true;
}
else
{
return false;
}
}
else if (Month == 4 || Month == 6 || Month == 9 || Month == 11)
{
if (Day >= 1 && Day <= 30)
{
return true;
}
else
{
return false;
}
}
else if (Month == 2 && IsLeapYear())
{
if (Day >= 1 && Day <= 29)
{
return true;
}
else
{
return false;
}
}
else if (Month == 2 && !IsLeapYear())
{
if (Day >= 1 && Day <= 28)
{
return true;
}
else
{
return false;
}
}
else
{
return false;
}
}
// Determine if year is a leap year
public Boolean IsLeapYear()
{
if ((Year % 4 == 0 && Year % 100 != 0) || (Year % 400 == 0))
{
return true;
}
else
{
return false;
}
}
// Print date to screen in format M/D/Y
public void DisplayDate()
{
Console.WriteLine(ShowDate());
}
public String ShowDate()
{
StringBuilder myStringBuilder = new StringBuilder();
myStringBuilder.AppendFormat("{0} / {1} / {2}", Month, Day, Year);
Console.WriteLine("{0}", myStringBuilder);
return (myStringBuilder.ToString());
}
static void Main(string[] args)
{
Date NewDate = new Date();
NewDate.SetDate(11,11,2011);
Console.ReadLine();
}
}

You never assign M, D or Y to your Month, Day and Year fields, so you are checking against your default values, which will all be zero by default. You could assign M, D and Y to their corresponding intended variables, but then you wouldn't be validating the input, just validating your fields. Instead you could have your methods accept parameters and check what you pass to it:
public Boolean ValidateMonth(int month)
{
if (month >= 1 && month <= 12)
{
return true;
}
else
{
return false;
}
}
And then when you call it
ValidateMonth(M);
And then you can do the same thing for the other two methods.
Also in your ValidateDate() method you have three useless calls to ValidateMonth(), ValidateDay() and ValidateYear(). You call each of these methods twice. (Once in the beginning, and then again in the if statement.) You can remove these:
public Boolean ValidateDate(int M, int D, int Y)
{
//Remove these:
//ValidateMonth();
//ValidateDay();
//ValidateYear();
if (ValidateMonth() && ValidateDay() && ValidateYear())
{
ShowDate();
return true;
}
else
{
return false;
}
}

Your constructor should initialize the class with the values given. Currently your default constructor initializes M, D, and Y but the constructor that takes arguments does not.
You can address this by changing the constructors to be more like this:
public Date() : this(1,1,1900)
{
}
public Date(int M, int D, int Y)
{
Month = M;
Day = D;
Year = Y;
}
Once the class is initialized, it's just a question of exposing a property or method to validate the values that are already held in the class. You shouldn't need to pass the month, day, and year into a method again, since they're already set. So the validate method might look like this:
public bool IsValid
{
get
{
return ValidateDay() && ValidateMonth() && ValidateYear();
}
}
And in your main program:
Date newDate = new Date(11,11,2011);
if (newDate.IsValid)
{
Console.WriteLine("Date is valid.");
}
else
{
Console.WriteLine("Date is not valid.");
}

c# array printing elements of multiple arrays [closed]

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Closed 6 years ago.
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Here is my code thus far; my main problem is in the main method.
namespace Lab
{
class dailyMenu
{
public static int r;
public string day;
public int date;
public string entree;
public double price;
public int calories;
public static int assignDate = 1;
public string Day
{
get { return day; }
set { day = value; }
}
public int Date
{
get { return date; }
set { date = value; }
}
public string Entree
{
get { return entree; }
set { entree = value; }
}
public double Price
{
get { return price; }
set { price = value; }
}
public int Calories
{
get { return calories; }
set { calories = value; }
}
private static string[] DayArray = { "Monday", "Tuesday", "Wednesday", "Thursday", "Friday" , "Saturday" , "Sunday" };
private static string[] EntreeArray = { "Pizza", "Spaghetti", "Cheeseburger", "Salad", "Soup", "Sandwich", "Pork", "Roast Chicken", "Kebab", "Steak", "Tacos", "Risotto" };
private static double[] PriceArray = { 2.50, 4.00, 1.50, 1.50, 1.50, 3.00, 3.50, 3.00, 2.50, 4.00, 3.00, 2.00 };
private static int[] CalorieArray = { 300, 600, 650, 270, 190, 680, 250, 300, 180, 250, 350, 600 };
public static void DayofMonth(int date)
{
date = assignDate;
assignDate++;
if (date == 5 || date == 12 || date == 19 || date == 26)
{
assignDate += 2;
}//end if
}// end DateofMonth
public static void DayofWeek (int day)
{
day = (day % 7) - 1;
}// end DayofWeek
public void randomItem()
{
Random rnd = new Random();
r = rnd.Next(0, 12);
this.entree = EntreeArray[r];
this.calories = CalorieArray[r];
this.price= PriceArray[r];
}// end randomItem
public dailyMenu()
{
randomItem();
}
static void Main(string[] args)
{
// Populates the 2D array
dailyMenu [,] day = new dailyMenu [4, 5];
for (int row = 0; row < 4; row ++)
{
for (int column = 0; column < 5; column++)
{
day[row, column] = new dailyMenu();
for (int i; r < Length.day; i++)
{
Console.WriteLine(r);
}
}//end forloop column
}// end forloop row
}//end Main
}//end dailyMenu
}//end namespace
I am trying to print out a new instance of DailyMenu with the three arrays using a for loop in Main, however the error message I'm getting is "The name Length does not exist in the current context."
Any help, please? Thanks.

You need to use day.Length not Length.day. day is your variable -- an array -- and it has a Length property.

One of the biggest problem I see with your code has to do with correctly naming your variables. Your class has a String property named 'day', you also declare a dailyMenu variable named 'day' in your main function and you also have an int parameter named 'day' in the DayOfWeek function. Talk about not helping with confusion. Name your things properly and you will have less problems.

How to parse by one line?

I am looking for a solution about how to get all of my int Parses within one line. At the moment when I start my program I have to enter day, month and year. It is all done line by line. I want a solution or method where this does all of my parsing within one line and within a format of "dd/MM/yyyy".
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace date
{
class Program
{
static void Main(string[] args)
{
Console.WriteLine("please enter date as dd/MM/yyyy");
int day;
int month;
int year;
day = int.Parse(Console.ReadLine());
month = int.Parse(Console.ReadLine());
year = int.Parse(Console.ReadLine());
Date i = new Date(day, month, year);
Console.WriteLine("{0}/{1}/{2}", i.day, i.month, i.year);
Console.ReadLine();
}
class Date
{
public int month; // 1-12
public int day; // 1-31 depending on month
int value = 1;
public int year
{
get;
private set;
}
public Date(int day, int month, int year)
{
this.day = day;
this.month = month;
this.year = year;
}
public int GetYear()
{
return year;
}
public void SetYear()
{
if (value > 1900 && value <= 2020)
year = value;
else
throw new ArgumentOutOfRangeException("year", value, "out of bounds");
}
private int Month
{
get { return month; }
set
{
if (value > 0 && value <= 12)
month = value;
else
throw new ArgumentOutOfRangeException("Month", value, "Month must be 1-12");
}
}
public int GetDay()
{
return day;
}
public void SetDay()
{
int[] days = { 0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 };
if (value > 0 && value <= days[month])
day = value;
else if (month == 2 && value == 29 &&
year % 400 == 0 || (year % 4 == 0 && year % 100 != 0))
day = value;
else
throw new ArgumentOutOfRangeException("days", value, "day is out of range");
}
}
}
}

You can use DateTime.Parse/TryParse or DateTime.ParseExact/TryParseExact:
string line = Console.ReadLine();
DateTime dt;
bool validDate = DateTime.TryParseExact(line,"dd/MM/yyyy", DateTimeFormatInfo.InvariantInfo,DateTimeStyles.None, out dt);
if(validDate)
Console.WriteLine(dt.ToLongDateString()); // now correctly initialized
With this format also DateTime.Parse/DateTime.TryParse works:
validDate = DateTime.TryParse(line, DateTimeFormatInfo.InvariantInfo, DateTimeStyles.None, out dt);
I use DateTimeFormatInfo.InvariantInfo to prevent that your local date separator is used instead of /(in case it's different).
Once it is parsed to DateTime it's trivial to create your Date instance:
Date d = new Date(dt.Day, dt.Month, dt.Year);

If you do NOT want to use DateTime.(Try)Parse, you can add a parse method with a Regex in your Date class:
public static Date ParseFromString(string s)
{
//string s = "24/12/2015";
Regex r = new Regex(#"(\d+)[\/](\d+)[\/](\d+)");
Match m = r.Match(s);
if (m.Success)
{
return new Date(m.Groups[1], m.Groups[2], m.Groups[3]);
}
else
{
// throw exception
}
}

You can't parse dd/MM/yyyy formatted string to int because it is not a valid string.
You need to parse it to DateTime first and you can use it's properties to get it's day, month and year as a numbers.
For example;
Console.WriteLine("please enter date as dd/MM/yyyy");
DateTime dt = DateTime.ParseExact(Console.ReadLine(), "dd/MM/yyyy",
CultureInfo.InvariantCulture);
int day = dt.Day;
int month = dt.Month;
int year = dt.Year;
Or you can use TryParseExact if you don't wanna throw exception if input is not dd/MM/yyyy format.
I am not wanting to use the preset DateTime class but I am using my
own "Date" class
If so, after you parse it, you can create your Date class instance with Date(int day, int month, int year) constructor based on this dt value as;
Date myDt = new Date(dt.Day, dt.Month, dt.Year);

Calculate DateTime for upcoming day of week

This is the code I have at the moment:
String getDayRequested;
public void setDay(String getDayFromForm1)
{
getDayRequested = getDayFromForm1;
{
if (getDayRequested.Contains("today"))
{
getDayRequested = DateTime.Today.DayOfWeek.ToString();
}
else if (getDayRequested.Contains("tomorrow"))
{
getDayRequested = DateTime.Today.AddDays(1).DayOfWeek.ToString();
}
}
This checks my TextBox.Text string from Form1, and checks to see if the text "today" or "tomorrow" is in it.
Can anyone help me in the right direction of how to check the string for information asked about upcoming days; ie: "What will be the date this saturday", and add the appropriate number of days depending on what the day is when asked.
UPDATE
Using the code in the accepted answer, I used the following in my above else if statement to complete what I was after:
else if (getDayRequested.Contains("monday"))
{
getDayRequested = GetFutureDay(DateTime.Now, DayOfWeek.Monday).ToString("dd");
}

This handy little method will return a future day of the week.
public DateTime GetFutureDay(DateTime start, DayOfWeek day)
{
int daysToAdd = (day - start.DayOfWeek + 7) % 7;
return start.AddDays(daysToAdd);
}
It would be called like:
var day = (DayOfWeek)Enum.Parse(typeof(DayOfWeek), getDayFromForm1);
var getDayRequested = GetFutureDay(DateTime.Now, day);

Consider the following snippet of code...
DateTime date;
public void setDay(String day)
{
DayOfWeek futureDay = (DayOfWeek)Enum.Parse(typeof(DayOfWeek), day);
int futureDayValue = (int)futureDay;
int currentDayValue = (int)DateTime.Now.DayOfWeek;
int dayDiff = futureDayValue - currentDayValue;
if (dayDiff > 0)
{
date = DateTime.Now.AddDays(dayDiff);
}
else
{
date = DateTime.Now.AddDays(dayDiff + 7);
}
}
Good Luck!

How to find out number of installments between two dates? [closed]

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Questions asking for code must demonstrate a minimal understanding of the problem being solved. Include attempted solutions, why they didn't work, and the expected results. See also: Stack Overflow question checklist
Closed 9 years ago.
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Suppose a Bank-Customer pays RD installments at every last day of the month.
So there must be 2 installments between the dates 12th October, 2013 and 10th December, 2013.
How can I find out how many installments the customer paid during this period of tine?
Should I use NodaTime library?
Ok. Here is my effort:
public sealed class DateDifference
{
int years;
public int Years
{
get { return years; }
}
int months;
public int Months
{
get { return months; }
}
int days;
public int Days
{
get { return days; }
}
public override string ToString()
{
return string.Format("[DateDifference Years={0}, Months={1}, Days={2}]", years, months, days);
}
public DateDifference(DateTime earlier, DateTime later)
{
if (later < earlier)
throw new ArgumentException("later is earlier than 'earlier'.");
bool isleapday = (earlier.Month == 2 && earlier.Day == 29);
DateTime tmp = isleapday ? new DateTime(earlier.Year, 2, 28) : earlier;
while (true)
{
try
{
tmp = tmp.AddYears(1);
if (isleapday && DateTime.IsLeapYear(tmp.Year))
tmp = new DateTime(tmp.Year, 2, 29);
}
catch (ArgumentOutOfRangeException)
{
break;
}
if (tmp <= later)
{
years++;
earlier = tmp;
}
else
{
break;
}
}
// Add months
tmp = earlier;
while (true)
{
try
{
tmp = tmp.AddMonths(1);
if (isleapday && tmp.Day != 29 && tmp.Month != 2)
tmp = new DateTime(tmp.Year, tmp.Month, 29);
}
catch (ArgumentOutOfRangeException)
{
break;
}
if (tmp <= later)
{
months++;
earlier = tmp;
}
else
{
break;
}
}
tmp = earlier;
while (true)
{
try
{
tmp = tmp.AddDays(1);
}
catch (ArgumentOutOfRangeException)
{
break;
}
if (tmp <= later)
{
days++;
earlier = tmp;
}
else
{
break;
}
}
}
DateDifference dateDifference = new DateDifference(startDateTextBox.Value, endDateTextBox.Value);
this.noOfInstallmentsTextBox.Text = ((int)++dateDifference.Months).ToString();

So I'll start off by saying I'm not prioritizing speed here. Datetime issues are tricky. Writing methods that you can be sure will work in all sorts of corner cases all over the world is hard. This approach is designed to work despite all edge cases and for that to be clear to the reader. It does not attempt to make cleaver optimizations because the tend to not work in odd edge cases, which are simply too common to ignore in the datetime world.
So first off we'll start with a simple helper method to get all of the days between two dates:
public static IEnumerable<DateTime> Days(DateTime start, DateTime end)
{
DateTime current = start;
while (current < end)
{
yield return current;
current = current.AddDays(1);
}
}
(If you want something more general purpose here you might get the next date after start, if you want all returned values to be "midnight". You might also swap start and end if they are in the reverse order, or throw an exception, etc. Also consider the exact semantics that you want; I have the bounds inclusive on start and exclusive on end, you may want it entirely inclusive, entirely exclusive, etc.)
We'll also create a method to determine if a date is the last day of the month.
public static bool IsLastDayOfMonth(DateTime date)
{
return date.AddDays(1).Month != date.Month;
}
We can actually define the last day of the month as being the only date for which its month is different from the following day's month.
Now when we combine these together we have an implementation that is very simple and clear to the reader:
public static int InstallmentCount(DateTime start, DateTime end)
{
return Days(start, end)
.Where(day => IsLastDayOfMonth(day))
.Count();
}

I hope it will help you.
int foo(DateTime start, DateTime end)
{
int count = end.Month - start.Month;
if (count < 0)
count += 12;
count += 12 * (end.Year - start.Year);
return count;
}