TimeIntervalSinceNow returns random numbers

Question

timeIntervalstores returned random numbers. I would have thought that the interval would continue to increase with each call, but sometimes I get negative numbers and sometimes positive numbers.

NSDate *date = groceryItem.lastPurchased;
double timeInterval = [date timeIntervalSinceNow];
cell.detailTextLabel.text = [NSString stringWithFormat:@"%d", timeInterval];

Answer 1

% d for integers, use% f for double

[NSString stringWithFormat:@"%f", timeInterval];

Answer 2

Try this instead:

NSTimeInterval timeInterval = [[NSDate date] timeIntervalSinceDate:groceryItem.lastPurchased];
cell.detailTextLabel.text = [NSString stringWithFormat:@"%f", timeInterval];

A few points in this snippet:

• I used NSTimeIntervalinstead doublein the second line. They are equivalent because it is just a typedef, but for a clearer code.
• , , [NSDate date] groceryItem.lastPurchased. , groceryItem.lastPurchased .
• , groceryItem.lastPurchased . , , , . , . , groceryItem.lastPurchasedDate, .

Answer 3

, . , date .

Answer 4

timeIntervalSinceNow . , . , , .

, .

Answer 5

[NSString stringWithFormat:@"%d", timeInterval]; . . % d. % f.

[NSString stringWithFormat:@"%f", timeInterval];

Answer 6

, , NSTimeInterval, double.

Answer 7

,

double timeInterval = - [date timeIntervalSinceNow];