C++迭代器需要删除吗？

Question

我有一个关于内存释放的问题

我正在我的一个程序中迭代一个 vector 。像这样:

// init vector
vector<int>* v = new vector<int>();
// iterate
for (vector<Column>::iterator it = v->begin(); it != v->end(); ++it) {
    // do something with it
}
// delete vector
delete v;

但是我不确定是否应该这样写:

// init vector
vector<int>* v = new vector<int>();
// iterate
vector<Column>::iterator it = v->begin()
for (; it != v->end(); ++it) {
    // do something with it
}
delete it;
// delete vector
delete v;

或者因为释放了迭代器而没有必要释放迭代器？

Answer 1

您只能对迭代器持有的对象调用 delete，而不是迭代器本身；以您的代码为例(但稍作修改):

std::vector<int*> *v = new std::vector<int*>();
for (int i = 0; i < 10; ++i) {
    v->push_back(new int(i));
}
std::vector<int*>::iterator it = v->begin();
for (; it != v->end(); ++it) {
    // do something with it
    delete *it; // <- notice the deference to delete the underlying int 
    //delete it; // causes compiler error (expected pointer)
}
// delete vector
delete v;

在迭代器类型上调用 delete 会产生编译器错误(取决于编译器/实现等)。