variable 'lat' may be uninitializated when used here - objective-c

Question

I'm trying to compile an Apple sample : KMLViewer, but Xcode show this error:
variable 'lat' may be uninitializated when used here
The code is this:
// Convert a KML coordinate list string to a C array of CLLocationCoordinate2Ds
// KML coordinate lists are longitude,latitude[,altitude] tuples specified by whitespace.
static void strToCoords(NSString *str, CLLocationCoordinate2D **coordsOut, NSUInteger *coordsLenOut)
{
NSUInteger read = 0, space = 10;
CLLocationCoordinate2D *coords = malloc(sizeof(CLLocationCoordinate2D) * space);
NSArray *tuples = [str componentsSeparatedByCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]];
for (NSString *tuple in tuples) {
if (read == space) {
space *= 2;
coords = realloc(coords, sizeof(CLLocationCoordinate2D) * space);
}
double lat, lon;
NSScanner *scanner = [[NSScanner alloc] initWithString:tuple];
[scanner setCharactersToBeSkipped:[NSCharacterSet characterSetWithCharactersInString:#","]];
BOOL success = [scanner scanDouble:&lon];
if (success)
success = [scanner scanDouble:&lat];
if (success) {
CLLocationCoordinate2D c = CLLocationCoordinate2DMake(lat, lon);
if (CLLocationCoordinate2DIsValid(c))
coords[read++] = c;
}
}
*coordsOut = coords;
*coordsLenOut = read;
}
The Xcode "solution" add 0.0 to double lat,lon (double lat = 0.0, lat), but does not work.
Any suggestion?

Answer 1

You need to have a default value for your variables as you only set them if certain conditions are met, but you use them regardless. This could lead to the variable not being set but you trying to use them. XCode is suggesting you default your variables to some value.
I.E:
double lat = 0.0;
double lon = 0.0;