Try to write location in a text file - iphone

Question

I am developing for jailbreak iPhones. I am reading Beginning iOS 5 book. Currently, I have used a location code from the book and changed it slightly. The change which I have made in the code is that I am writing the location in a text file. But the program crashes. Although the same program without any modification is working perfectly.
Here is the code:
- (void)viewDidLoad
{
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
self.locationManager = [[CLLocationManager alloc] init];
locationManager.delegate = self;
locationManager.desiredAccuracy = kCLLocationAccuracyBest;
locationManager.distanceFilter = 2.0f;
[locationManager startUpdatingLocation];
}
- (void)locationManager:(CLLocationManager *)manager
didUpdateToLocation:(CLLocation *)newLocation
fromLocation:(CLLocation *)oldLocation
{
FILE *file = fopen("/usr/locations.txt", "a");
if (!file)
{
fprintf(file, "Error opening file");
}
if (startingPoint == nil)
self.startingPoint = newLocation;
NSString *latitudeString = [NSString stringWithFormat:#"%g\u00B0",
newLocation.coordinate.latitude];
latitudeLabel.text = latitudeString;
NSNumber *latitude = [[NSNumber alloc] initWithDouble:newLocation.coordinate.latitude];
NSNumber *longitude = [[NSNumber alloc] initWithDouble:newLocation.coordinate.longitude];
NSString *longitudeString = [NSString stringWithFormat:#"%g\u00B0",
newLocation.coordinate.longitude];
longitudeLabel.text = longitudeString;
NSString *horizontalAccuracyString = [NSString stringWithFormat:#"%gm",
newLocation.horizontalAccuracy];
horizontalAccuracyLabel.text = horizontalAccuracyString;
NSString *altitudeString = [NSString stringWithFormat:#"%gm",
newLocation.altitude];
altitudeLabel.text = altitudeString;
NSString *verticalAccuracyString = [NSString stringWithFormat:#"%gm",
newLocation.verticalAccuracy];
verticalAccuracyLabel.text = verticalAccuracyString;
CLLocationDistance distance = [newLocation
distanceFromLocation:startingPoint];
NSString *distanceString = [NSString stringWithFormat:#"%gm", distance];
distanceTraveledLabel.text = distanceString;
struct tm *local;
time_t t;
t = time(NULL);
local = localtime(&t);
fprintf(file, "Local time and Date: %s ", asctime(local));
//----------------- ------------------------------------------------------------
fprintf(file, "Latitude = %lf, Longitude = %lf \n",
newLocation.coordinate.latitude, newLocation.coordinate.longitude);
fclose(file);
}

Answer 1

Your most recent comment on the question says you want to print to the console instead. In order to print on the console you use NSLog(). When you use the format specifier for an object %#, the string substituted for the object is the object’s description method.
To print the location on the console use
NSLog(#"New location: %#", newLocation);
NSLog(#"Old location: %#", oldLocation);
The description method on CLLocation returns “A string of the form ‘latitude, longitude +/- accuracy m (speed kph / heading) # date-time’.”