sort

Unreasonable Input in std sort Lambda Expression

by 
	struct Aa
	{
		int i0;
	};
	std::vector<Aa*> list_;
...
	std::sort(list_.begin(), list_.end(), [this, &end_dates](Aa* l, Aa* r) {
		return l->degree_ - r->degree_;
	});

Before the sort, I promise the members of list_ are all not null, but in the sort lambda expression, when running, we will be caught by a null pointer access SIGSEGV, for example, l is null.

Well, the good shot is,

...
	std::sort(list_.begin(), list_.end(), [this, &end_dates](Aa* l, Aa* r) {
		return l->degree_ > r->degree_;
	});