Rounding numbers in Objective-C

Hi,

I'm trying to do some number rounding and conversion to a string to enhance the output in an Objective-C program.

I have a float value that I'd like to round to the nearest .5 and then use it to set the text on a label.

For example:

1.4 would be a string of: 1.5

1.2 would be a string of: 1

0.2 would be a string of: 0

I've spent a while looking on Google for an answer but, being a noob with Objective-C, I'm not sure what to search for! So, I'd really appreciate a pointer in the right direction!

Thanks, Ash

From stackoverflow

• I'd recommend looking into using NSNumberFormatter.

• NSString *numberString = [NSString stringWithFormat:@"%f", round(2.0f * number) / 2.0f];
  

• Thanks for the pointers everyone, I've managed to come up with a solution:

  float roundedValue = round(2.0f * number) / 2.0f;
  NSNumberFormatter *formatter = [[NSNumberFormatter alloc] init];
  [formatter setMaximumFractionDigits:1];
  [formatter setRoundingMode: NSNumberFormatterRoundDown];
  
  NSString *numberString = [formatter stringFromNumber:[NSNumber numberWithFloat:roundedValue]];
  [formatter release];
  

  The above works for the test cases I threw at it, but if anyone knows a better way to do this I'd be interested to hear it!

  Chuck : If this is being output to a text field, you can just attach the formatter to the field.

• Use lroundf() to round a float to integer and then convert the integer to a string.

• NSString *numberString = [NSString stringWithFormat:@"%d",lroundf(number)];