How to tell amount of hours since NSDate - iphone

Question

I initiated an NSDate with [NSDate date]; and I want to check whether or not it's been 5 hours since that NSDate variable. How would I go about doing that? What I have in my code is
requestTime = [[NSDate alloc] init];
requestTime = [NSDate date];
In a later method I want to check whether or not it's been 12 hours since requestTime. Please help! Thanks in advance.

Answer 1

NSInteger hours = [[[NSCalendar currentCalendar] components:NSHourCalendarUnit fromDate:requestTime toDate:[NSDate date] options:0] hour];
if(hours >= 5)
// hooray!

Answer 2

int seconds = -(int)[requestTime timeIntervalSinceNow];
int hours = seconds/3600;
Basically here I'm asking how many seconds have passed since we first got our requestTime. Then with a little math magic, aka dividing by the number of seconds in an hour, we can get the number of hours that have passed.
A word of caution. Make sure you use the "retain" keyword when setting the requesttime. xcode likes to forget what NSDate objects are set to without it.
requestTime = [[NSDate date] retain];

Answer 3

Try using this method, or something along these lines.
- (int)hoursSinceDate :(NSDate *)date
{
#define NUBMER_OF_SECONDS_IN_ONE_HOUR 3600
NSDate *currentTime = [NSDate date];
double secondsSinceDate = [currentTime timeIntervalSinceDate:date];
return (int)secondsSinceDate / NUBMER_OF_SECONDS_IN_ONE_HOUR;
}
You can then do a simple check on the integer hour response.
int hours = [dateUtilityClass hoursSinceDate:dateInQuestion];
if(hours < 5){
# It has not yet been 5 hours.
}