OC17 memory management and automatic reference counting

  VIEWCONTROLLER.M//  OC17 memory management and automatic reference counting////  created by zoujie  ON 15/10/25.//  COPYRIGHT ? 2015 year  zoujie. all rights reserved.//# import  "ViewController.h" #import   "Fraction.h" @interface  ViewController  () @ end@implementation viewcontroller-  (void) viewdidload {    [super  Viewdidload]; #pragma  mark  basic knowledge of memory management/application not enough memory to sit more things, there is a possibility of collapse. Memory management is concerned with cleaning up (recycling) unused memory so that memory can be reused.     1. Frees memory//    2 that are not used by objects. Determines that the object does not need to use//    3. Reference count (manual, used to support legacy non-ARC engineering)     [self managermemorybymyself];//    4. Xcode4.2 after   ARC  Auto reference count     [self autoARC];         }-(void) managermemorybymyself{//     when an object is created, the initial reference count is 1//      whenever creating a reference to an object needs to be a reference object +1  , send RetaiN Message     id obj,obj1;//    [obj retain];//      &NBSP by sending the release message to an object when the object is not needed; 1//    [obj release];    for reference counting  //     when the reference count is 0, the system knows that the object is not required to use     //     The Add method   adds a reference count     [obj addObject:obj1];    [obj  Addsubview:obj1];    //    remove will reduce the object reference count     [obj  removeObjectAtIndex:0];    [obj removeFromSuperview];         //    NSAutoreleasePool  Auto-release pools can help track objects that need to be released for some time to delay, By sending an drain message to the auto-release pool, the auto-free pool is cleaned up and the object is freed//    [obj1 autorelease];         Fraction *frac1 = [[Fraction alloc]init];     Fraction *frac2 = [[fraction alloc]init];    //    [frac1 release];//     [frac2 release];            }-( void) autoarc{}-  (void) didreceivememorywarning {    [super  Didreceivememorywarning];    // dispose of any resources that  can be recreated.} @end

OC17 memory management and automatic reference counting