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Subtract 2 Dates

mike rich

Joined: Jan 30, 2002
Posts: 2
I need to calculate the number of days between 2 dates. I think I have confused myself beyond repair and I am seeking some advice. Below is a snip of my code. In a nutshell I am reading 2 string values, converting them to date and then I want to calculate the difference. any help would be appreciated.....
String ds1 = a[x].getinvoice().substring(date_start, last_paren);
String ds2 = a[x].getdate().trim();

DateFormat dt_parse1 = DateFormat.getDateInstance((DateFormat.SHORT));
DateFormat dt_parse2 = DateFormat.getDateInstance((DateFormat.SHORT));

Date d1 = dt_parse1.parse(ds1);
Date d2 = dt_parse1.parse(ds2);

SimpleDateFormat local_format1 = new SimpleDateFormat("MM/dd/yy");
SimpleDateFormat local_format2 = new SimpleDateFormat("MM/dd/yy");

System.out.println("New Date1: " + local_format1.format(d1));
System.out.println("New Date2: " + local_format1.format(d2));

/*Gregorian*/Calendar cal1 = new GregorianCalendar();

/*Gregorian*/Calendar cal2 = new GregorianCalendar();

System.out.println("New Date1 as calendar object: " + local_format1.format(cal1.getTime()));
System.out.println("New Date2 as calendar object: " + local_format1.format(cal2.getTime()));
System.out.println("********** " + (local_format1.format(cal1.getTime()) - local_format1.format(cal2.getTime())));

catch (ParseException p)
Dave Vick
Ranch Hand

Joined: May 10, 2001
Posts: 3244
mike r
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Marilyn de Queiroz

Joined: Jul 22, 2000
Posts: 9059
I would use some of the methods in the Date class.

"Yesterday is history, tomorrow is a mystery, and today is a gift; that's why they call it the present." Eleanor Roosevelt
Frank Carver

Joined: Jan 07, 1999
Posts: 6920
It's really important to step back and think about the data types in this problem. It's a surprisingly common one.
What is the conceptual data type of the difference between two dates? If you were making a class to hold the difference between two dates, what would you call it?
Hint: it's not a Date.

Read about me at ~ Raspberry Alpha Omega ~ Frank's Punchbarrel Blog
Snigdha Solanki
Ranch Hand

Joined: Sep 07, 2000
Posts: 128
Check out the following code:

where the input dates have format month, day,
year eg ( 6 , 2, 1983 means June 2, 1983)

Snigdha<br />Sun Certified Programmer for the Java™ 2 Platform
I agree. Here's the link:
subject: Subtract 2 Dates
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