Defining a 'Watch' class
You should definitely check out how properties can make your code shorter, by adding some standard setter/getter 

@interface Watch: NSObject

@property int hours;
@property int minutes;
-(void) printTime;

@end


@implementation Watch 

-(void) printTime
{
    NSLog(@"Time is %i:%i", _hours, _minutes);
}

@end


Also the naming convention of a getter is the property name

int main(int argc, const char * argv[])
{

    @autoreleasepool
    {
        Watch *myWatch = [[Watch alloc]init];
        [myWatch setHours: 5];
        [myWatch setMinutes: 30];

        int hours = [myWatch hours]; //standard getter
        int minutes = [myWatch minutes];
        [myWatch printTime];
    }
    return 0;
}


naming conventions are important in Cocoa, as higher level technologies as Key-Value-Observing depends on them.