Comparing dates

Question

In my application I need to compare three dates in one if-else cycle. I have a start date, end date and the date of testing. What I want to check is whether the test date is between the start date and end date.

if (testDate >= startDate && testDate <= endDate) {

If I set the startDate to 25/04/2012 and the endDate to 24/04/2019 and the testDate to 25/12/2013 the code works. But if i set the startDate to 26/04/2000 and the endDate to 24/04/2019 and the testDate to 25/12/2013 the code does not works. What's wrong?

Yes, you're comparing object addresses. You must use a compare method supported by the object. — Hot Licks, Apr 27 '12 at 17:14

score 3 · Answer 1 · answered Apr 27 '12 at 17:10

3

You cannot sanely compare Objective-C objects with any boolean operators in C. You'd be comparing their addresses, not their values.

Look at the documentation for the NSDate class, specifically the -compare: method.

answered Apr 27 '12 at 17:10

Jonathan Grynspan

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score 2 · Accepted Answer · answered Apr 27 '12 at 17:15

Dates can be compared like that. However, you must first call timeIntervalSince1970 to convert the date to an integer type value. In this case, it gives you a numeric value of type NSTimeInterval.

The other option is to use the compare: method invoked on the NSDate object.

In that case, comparing one date to another will give a result detailed in the class reference as follows:

The receiver and anotherDate are exactly equal to each other, NSOrderedSame
The receiver is later in time than anotherDate, NSOrderedDescending
The receiver is earlier in time than anotherDate, NSOrderedAscending.

Comparing dates

2 Answers2