Objective C programming language attributes

Wypisywanie w konsoli:

NSLog(@"%@", strValue);
NSLog(flag ? @"Yes" : @"No");

• For Strings you use %@
• For int you use %i
• For float and double you use %f
• For bool you use %d

Consty i zmienne:

const char NEWLINE = '\n';
int area;  

Tworzenie klas i obiektów:

@interface SampleClass:NSObject
- (void)sampleMethod;
@end

@implementation SampleClass
- (void)sampleMethod {
   NSLog(@"Hello, World! \n");
}
@end

int main() {
   /* my first program in Objective-C */
   SampleClass *sampleClass = [[SampleClass alloc]init];
   [sampleClass sampleMethod];
   return 0;
}

Tworzenie struct:

struct Books {
   NSString *title;
   NSString *author;
   NSString *subject;
   int   book_id;
};

Manipulowanie struct:

@interface BookLogger:NSObject
/* function declaration */
- (void) printBook:(struct Books*) book;
@end

@implementation BookLogger
- (void) printBook:(struct Books*) book {
   NSLog(@"Book title: %@\n", book->title);
   NSLog(@"Book author: %@\n", book->author);
   NSLog(@"Book subject: %@\n", book->subject);
   NSLog(@"Book book_id: %d\n", book->book_id);
}
@end

int main() {
   struct Books Book1;        /* Declare Book1 of type Book */
   struct Books Book2;        /* Declare Book2 of type Book */

  BookLogger *bookLogger = [[BookLogger alloc]init];
  /* print Book1 info */
  [sampleClass bookLogger: Book1];
}

Tworzenie bloków funkcji:

- (return_type) method_name:(argumentType1)argumentName1 
joiningArgument2:(argumentType2)argumentName2 ... 
joiningArgumentn:(argumentTypen)argumentNamen {
   body of the function
}

i.e.:

double (^multiplyTwoValues)(double, double) = 
   ^(double firstValue, double secondValue) {
      return firstValue * secondValue;
   };

double result = multiplyTwoValues(2,4); 
NSLog(@"The result is %f", result);

Struktury danych:

• NSDictionary could be accessed like dict[@"key"] or [dict objectForKey:@"key"]
• NSArray is accessible via indexes: 0, 1, 2 etc:

Inicjacja NSArray:

NSArray* array = @[@"One", @"Two", @"Three"];
NSArray* array = @[Object1, Object2]

Iterowanie po NSDictionary:

for (NSString* key in yourDict) {
    NSLog(@"%@", yourDict[key]);
    //or
    NSLog(@"%@", [yourDict objectForKey:key]);
}

Inicjalizacja NSDictionary:

NSDictionary* dict = @{ key : value, key2 : value2};

Dodawanie do NSDictionary wartości niebędającej obiektem wymaga jej rzutowania na odpowiedni obiekt Objective C:

@"facebookId": [NSNumber numberWithInt:[fbId intValue]];
@"facebookId": @(fbId) // for non pointer datatype value store in Dictionary

@property:

atomic, nonatomic, etc.

@synthesize:

@synthesize