Round doubles in Objective-C

Question

I have double number in a format like 34.123456789. How can I change it to 34.123?

I just want 3 digits after the decimal point.

Answer 1

If you want to make

34.123456789 -> 34.123
34.000000000 -> 34 not 34.000

You can use NSNumberFormatter

NSNumberFormatter *fmt = [[NSNumberFormatter alloc] init];
[fmt setMaximumFractionDigits:3]; // 3 is the number of digits

NSLog(@"%@", [fmt stringFromNumber:[NSNumber numberWithFloat:34.123456789]]);  // print 34.123
NSLog(@"%@", [fmt stringFromNumber:[NSNumber numberWithFloat:34.000000000]]);  // print 34