[Guo yu jumped to the cliff] play weak, strong, and arcweak under arc

[Guo yu jumped to the cliff] play weak, strong, and arcweak under arc
Strong: as long as I still reference you with strong, you will not be dealloc. Weak: I only use weak to reference you. Only when someone else strong references you will I be valid for your weak reference.
This is like Guo Yi's jump to the cliff, Guo Jing Huang Rong rushed to the horse, all reached out to grasp Guo Yi, formed two strong references. After Guo fu arrived, he could only watch it. It was a weak reference, and Guo Jing was quoted by Guo Jing Huang Rong as two strong references. If Guo Jing Huang Rong does not hold down and the two strong references are set to nil, Guo Fu's eye reference means that the weak reference will immediately expire-Guo yu jumped into the deep Cliff and won't be seen (dealloc ).