Re: scenario's under which Container invalidate its iterator
Jeff Schwab wrote:
Pallav singh wrote:
1. Uninitialized iterators:
vector<int>::iterator it;
it++;
Undefined Behavior
2. Out of range access:
vector<int>::iterator it = vec.end();
it++;
Undefined Behavior
3. Comparing iterators from different ranges or containers:
for (it = vec1.begin(); it != vec2.end(); ++it)
Implementation-defined Behavior
4. use of invalidated or "dangling" iterators:
vector<int> it = vec.begin();
vec.clear();
it++;
Undefined Behavior
None of those have anything to do with invalidating iterators.
Jeff,
That's not entirely accurate. In the case 4, if 'vec' had elements at
the time of calling 'begin', has 'it' valid *until* it is *invalidated*
by the subsequent deletion of the element to which 'it' refers when the
program calls 'vec.clear()'. So, the correct choice is 4 (for the OP's
test, or so it seems).
To the OP:
Next time post your question correctly, as in "I have a test to
complete. Here is the question, and here are the choices. Could you
please answer the question for me and give me a detailed explanation why
that is the correct answer, please? Thank you in advance." Of course,
you can run into "do your own homework" response (and more likely that
way, no doubt), but at least you're going to be honest with the group
regarding the problem you're trying to solve.
V
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