看下面的程序,第一个NSLog会输出什么?这时str的retainCount是多少?第二个和第三个呢? 为什么?

NSMutableArray* ary = [[NSMutableArray array] retain];
NSString *str = [NSString stringWithFormat:@”test”];
[str retain];
[aryaddObject:str];
NSLog(@”%@%d”,str,[str retainCount]);
[str retain];
[str release];
[str release];
NSLog(@”%@%d”,str,[str retainCount]);
[aryremoveAllObjects];
NSLog(@”%@%d”,str,[str retainCount]);
str的retainCount创建+1，retain+1，加入数组自动+1 3

retain+1，release-1，release-1 2

数组删除所有对象，所有数组内的对象自动-1 1