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-rw-r--r--objective-c.html.markdown58
1 files changed, 49 insertions, 9 deletions
diff --git a/objective-c.html.markdown b/objective-c.html.markdown
index 1cfe8ed6..0131a34c 100644
--- a/objective-c.html.markdown
+++ b/objective-c.html.markdown
@@ -50,53 +50,93 @@ int main (int argc, const char * argv[])
// String
NSString *worldString = @"World";
- NSLog(@"Hello %@!", worldString); // Print "Hello World!"
+ NSLog(@"Hello %@!", worldString); // prints => "Hello World!"
+ // The mutable version of NSString is NSMutableString that allows to edit
+ // individual characters or append strings together.
+ NSMutableString *mutableString = [NSMutableString stringWithString:@"Hello"];
+ [mutableString appendString:@" World!"];
+ NSLog(@"%@", mutableString); // prints => "Hello World!"
// Character literals
NSNumber *theLetterZNumber = @'Z';
- char theLetterZ = [theLetterZNumber charValue];
+ char theLetterZ = [theLetterZNumber charValue]; // or 'Z'
NSLog(@"%c", theLetterZ);
// Integral literals
NSNumber *fortyTwoNumber = @42;
- int fortyTwo = [fortyTwoNumber intValue];
+ int fortyTwo = [fortyTwoNumber intValue]; // or 42
NSLog(@"%i", fortyTwo);
NSNumber *fortyTwoUnsignedNumber = @42U;
- unsigned int fortyTwoUnsigned = [fortyTwoUnsignedNumber unsignedIntValue];
+ unsigned int fortyTwoUnsigned = [fortyTwoUnsignedNumber unsignedIntValue]; // or 42
NSLog(@"%u", fortyTwoUnsigned);
NSNumber *fortyTwoShortNumber = [NSNumber numberWithShort:42];
- short fortyTwoShort = [fortyTwoShortNumber shortValue];
+ short fortyTwoShort = [fortyTwoShortNumber shortValue]; // or 42
NSLog(@"%hi", fortyTwoShort);
+
+ NSNumber *fortyTwoShortNumber = [NSNumber numberWithShort:41];
+ unsigned short fortyTwoUnsigned = [fortyTwoShortNumber unsignedShortValue]; // or 41
+ NSLog(@"%hu", fortyTwoUnsigned);
NSNumber *fortyTwoLongNumber = @42L;
- long fortyTwoLong = [fortyTwoLongNumber longValue];
+ long fortyTwoLong = [fortyTwoLongNumber longValue]; // or 42
NSLog(@"%li", fortyTwoLong);
+ NSNumber *fortyTwoLongNumber = @53L;
+ unsigned long fiftyThreeUnsigned = [fortyTwoLongNumber unsignedLongValue]; // or 53
+ NSLog(@"%lu", fiftyThreeUnsigned);
+
// Floating point literals
NSNumber *piFloatNumber = @3.141592654F;
- float piFloat = [piFloatNumber floatValue];
- NSLog(@"%f", piFloat);
+ float piFloat = [piFloatNumber floatValue]; // or 3.141592654f
+ NSLog(@"%f", piFloat); // prints => 3.141592654
+ NSLog(@"%5.2f", piFloat); // prints => " 3.14"
NSNumber *piDoubleNumber = @3.1415926535;
- double piDouble = [piDoubleNumber doubleValue];
+ double piDouble = [piDoubleNumber doubleValue]; // or 3.1415926535
NSLog(@"%f", piDouble);
+ NSLog(@"%4.2f", piDouble); // prints => "3.14"
+
+ // NSDecimalNumber is Objective-C's fixed-point class more precise then float or double
+ NSDecimalNumber *oneDecNum = [NSDecimalNumber decimalNumberWithString:@"10.99"];
+ NSDecimalNumber *twoDecNum = [NSDecimalNumber decimalNumberWithString:@"5.002"];
+ // NSDecimal isn't able to use standard +, -, *, / operators. NSDecimalNumber has its own:
+ [oneDecNum decimalNumberByAdding:twoDecNum]; // add
+ [oneDecNum decimalNumberBySubtracting:twoDecNum];
+ [oneDecNum decimalNumberByMultiplyingBy:twoDecNum];
+ [oneDecNum decimalNumberByDividingBy:twoDecNum];
+ NSLog(@"%@", oneDecNum); // prints => 10.99 as NSDecimalNumber is immutable.
// BOOL literals
NSNumber *yesNumber = @YES;
NSNumber *noNumber = @NO;
+ // or
+ BOOL yesBool = YES;
+ BOOL noBool = NO;
+ NSLog(@"%i", yesBool); // prints => 1
// Array object
NSArray *anArray = @[@1, @2, @3, @4];
NSNumber *thirdNumber = anArray[2];
NSLog(@"Third number = %@", thirdNumber); // Print "Third number = 3"
+ // NSMutableArray is mutable version of NSArray allowing to change items in array
+ // and extend or shrink array object. Convenient, but not as efficient as NSArray.
+ NSMutableArray *mutableArray = [NSMutableArray arrayWithCapacity:2];
+ [mutableArray addObject:@"Hello"];
+ [mutableArray addObject:@"World"];
+ [mutableArray removeObjectAtIndex:0];
+ NSLog(@"%@", [mutableArray objectAtIndex:0]); // prints => "World"
// Dictionary object
NSDictionary *aDictionary = @{ @"key1" : @"value1", @"key2" : @"value2" };
NSObject *valueObject = aDictionary[@"A Key"];
NSLog(@"Object = %@", valueObject); // Print "Object = (null)"
+ // Set object
+ NSSet *set = [NSSet setWithObjects:@"Hello", @"Hello", @"World", nil];
+ NSLog(@"%@", set); // prints => {(Hello, World)}
+
///////////////////////////////////////
// Operators
///////////////////////////////////////