#import "ViewController.h"
@interface ViewController ()
@property (retain,nonatomic) NSString *myRetainStr;
@property (copy, nonatomic) NSString *myCopyStr;
@property (strong, nonatomic) NSString *myStrongStr;
@end
@implementation ViewController
- (void)viewDidLoad {
[super viewDidLoad];
//[self testNSMutableStringCopyRetain];
//[self testNSStringCopyRetain];
//[self testNSStringStrongRetain];
[self testNSMutableStringStrongRetain];
//结论
//retain和strong对于nsstrong和nsmutablestring效果都一样。都是指向一个地址。
//对于nstring,retain和copy效果也一样。都是指向同一个地址。
//对于nsmutablestring，retain和copy效果不一样。retain添加一个引用计数。copy实现深复制。
//所以，nstring和nsmutablestring在一般情况下用copy修饰符都是完全正确的。
}
//NSMutableString的retain和copy区别
-(void)testNSMutableStringCopyRetain{
NSMutableString *mStr = [NSMutableString stringWithFormat:@"abc"];
self.myRetainStr = mStr;
self.myCopyStr = mStr;
NSLog(@"mStr:%p,%p", mStr,&mStr);
NSLog(@"retainStr:%p,%p", _myRetainStr, &_myRetainStr);
NSLog(@"copyStr:%p,%p", _myCopyStr, &_myCopyStr);
// 2015-06-10 14:49:38.757 strong retain copy nsstring区别[6812:359227] mStr:0x7fed98536cd0,0x7fff56a199b8
// 2015-06-10 14:49:38.758 strong retain copy nsstring区别[6812:359227] retainStr:0x7fed98536cd0,0x7fed98541fd8
// 2015-06-10 14:49:38.758 strong retain copy nsstring区别[6812:359227] copyStr:0x7fed9853db50,0x7fed98541fe0
//从运行结果看出,对于NSMutableString retain是添加引用计数。 copy是深复制
}
//NSString的retain和copy区别
-(void)testNSStringCopyRetain{
NSString *mStr = [NSString stringWithFormat:@"abc"];
self.myRetainStr = mStr;
self.myCopyStr = mStr;
NSLog(@"mStr:%p,%p", mStr,&mStr);
NSLog(@"retainStr:%p,%p", _myRetainStr, &_myRetainStr);
NSLog(@"copyStr:%p,%p", _myCopyStr, &_myCopyStr);
// 2015-06-10 14:53:19.822 strong retain copy nsstring区别[6847:361075] mStr:0x7fbc00c44c30,0x7fff547b69b8
// 2015-06-10 14:53:19.822 strong retain copy nsstring区别[6847:361075] retainStr:0x7fbc00c44c30,0x7fbc00d12d58
// 2015-06-10 14:53:19.822 strong retain copy nsstring区别[6847:361075] copyStr:0x7fbc00c44c30,0x7fbc00d12d60
//从运行结果看出,对于NSString来看 retain是添加引用计数。 copy是浅复制。他们之间没有区别
}
//NSString的retain和Strong区别
-(void)testNSStringStrongRetain{
NSString *mStr = [NSString stringWithFormat:@"abc"];
self.myRetainStr = mStr;
self.myStrongStr = mStr;
NSLog(@"mStr:%p,%p", mStr,&mStr);
NSLog(@"retainStr:%p,%p", _myRetainStr, &_myRetainStr);
NSLog(@"StrongStr:%p,%p", _myStrongStr, &_myStrongStr);
// 2015-06-10 14:57:41.983 strong retain copy nsstring区别[6919:363984] mStr:0x7f894a49db90,0x7fff5aaf69b8
// 2015-06-10 14:57:41.983 strong retain copy nsstring区别[6919:363984] retainStr:0x7f894a49db90,0x7f894a543db8
// 2015-06-10 14:57:41.983 strong retain copy nsstring区别[6919:363984] StrongStr:0x7f894a49db90,0x7f894a543dc8
//从运行结果看出,对于NSString来看 retain是添加引用计数。 strong是浅复制。 效果都一样。指向同一个地址
}
//NSMutableString的retain和Strong区别
-(void)testNSMutableStringStrongRetain{
NSMutableString *mStr = [NSMutableString stringWithFormat:@"abc"];
self.myRetainStr = mStr;
self.myStrongStr = mStr;
NSLog(@"mStr:%p,%p", mStr,&mStr);
NSLog(@"retainStr:%p,%p", _myRetainStr, &_myRetainStr);
NSLog(@"StrongStr:%p,%p", _myStrongStr, &_myStrongStr);
// 2015-06-10 15:01:54.719 strong retain copy nsstring区别[6963:366057] mStr:0x7f9033715590,0x7fff58f749b8
// 2015-06-10 15:01:54.720 strong retain copy nsstring区别[6963:366057] retainStr:0x7f9033715590,0x7f9033617e28
// 2015-06-10 15:01:54.720 strong retain copy nsstring区别[6963:366057] StrongStr:0x7f9033715590,0x7f9033617e38
//从运行结果看出,对于NSString来看 retain是添加引用计数。 strong是浅复制。 效果都一样。指向同一个地址
}