Hi, i need a little help i have a method which gets value such as 50, it then assigns that value to trackDuration, so NSNumber *trackDuration = 50, i want the method to every second minus 1 from the value of trackDuration and update a label, the label being called duration.

Here's what i have so far;

- (void) countDown {
iTunesApplication *iTunes = [SBApplication applicationWithBundleIdentifier:@"com.apple.iTunes"];

NSNumber *trackDuration = [NSNumber numberWithDouble:[[iTunes currentTrack] duration]];
while (trackDuration > 0) {
    trackDuration - 1;
    int inputSeconds = [trackDuration intValue];
    int hours =  inputSeconds / 3600;
    int minutes = ( inputSeconds - hours * 3600 ) / 60; 
    int seconds = inputSeconds - hours * 3600 - minutes * 60; 
    NSString *trackDurationString = [NSString stringWithFormat:@"%.2d:%.2d:%.2d", hours, minutes, seconds];
    [duration setStringValue:trackDurationString];
    sleep(1);
}}

Any help would be much appreciated, thanks in advanced, Sami.