Memory General And methods

Variable & Object Types

BOOL

Values:- YES, NO

NSLog(@”The answer is %i”, MyValue);

char
UInt8
int

32bits (currently unless the iPhone ever moves to a 64bit chipset).  If you want to future protect pointers for a 64bit system you can use NSInteger instead.

NSLog(@”Value = %i”, MyValue);

long long / unsigned long long
float

NSLog(@”Value = %f”, MyValue);

double

NSLog(@”Value = %f”, MyValue);

NSString
NSDate
NSObject

Most classes in Objective-C are derived from NSObject:

    NSObject *object;
    object = [[NSObject alloc] init];
    NSLog(@"object = %@", object);
    [object release];

id

You may be working with an object but you are not sure what that object will be when the code executes. The id variable can be used as a sort of placeholder for any object. It is often used in the Cocoa-Touch frameworks and it is one of the things that contributes to the powerful flexibility of the Objective-C programming language.

    id someObject;
    someObject = object;
    NSLog(@"some object = %@", someObject);

Currency

A good way is to use NSNumber and NSNumberFormatter together so that the currency will always be localized for whatever country the device is in.

        NSNumber *MyValue = [NSNumber numberWithFloat:29.99];
        NSNumberFormatter *numberFormatter = [[NSNumberFormatter alloc] init];
        numberFormatter.numberStyle = kCFNumberFormatterCurrencyStyle;
        NSLog(@"The cost is %@", [numberFormatter stringFromNumber:MyValue]);
        [numberFormatter release];

static

Use static as for normal C to declare static variables:

        static NSString *SomeStringName;

self (this)

self is the address of the object running the current method.  It’s like ‘this’ in VC++.  Typically it’s used so that an object can send a message to itself:

        [self SomeMethodName];

super

super is used when you want to send a message to the self, but in it’s super class (instead of th method being looked for in the local class first):

        [super SomeMethodName];