An iterator point to nowhere?

[northfly]

I defined the following function to find out the iterator of a certain value in the vector. I defined it as such so if the value exist in the vector then return a iterator of it, if not then return a pointer pointing to nonsense.:

vector<tIndex_t>::iterator unlabelTit(const tIndex_t index) {
	for(vector<tIndex_t>::iterator it=unlabelT.begin(); it<unlabelT.end(); it++) {
		if(index==*it) return it;
	}
    return NULL;
}

But looks this one is not accepted by compiler, saying I cannot do this kind of comparison like:

unlabelTit(i)!=NULL;

so I just delete the return NULL; and then the compiler giving me warning about no return statement before }.

a pointer pointing to nonsense? how to do that?

[Zhuge]

I'd say the proper behavior is to return an iterator pointing to end() (1 past the end of the container, and thus it is invalid in all cases); this is what all standard find functions do, and what it looks like you are trying to to with your function.

[Daleth]

Iterators are not comparable to NULL like pointers. STL algorithms return Container.end() instead.

[northfly]

THanks!!!