CODEWITHSUNDEEP
c++vectorstderase
Zebrafish
Zebrafish

Reputation: 13876

Do these two ways of deleting vector pointers result in the same thing?

I was wondering if in this case I could use the std::vector::resize() function instead of the erase(). I was wondering in the following case whether the ::erase() and ::resize() would do the same thing:

struct Foo
{
    int* a = new int[10];
    ~Foo() { delete[] a; }
};

int main()
{
    std::vector<Foo*> fooVector;

    // FILL VECTOR WITH 100 FOO OBJECT POINTERS
    int i = 100;
    while (--i) fooVector.push_back(new Foo);

    // DELETE LAST 50 FOO OBJECTS
    for (int i = 50; i < 100; ++i)
        delete fooVector[i];

    // ERASE LAST 50 VECTOR ELEMENTS (POINTERS)
    fooVector.erase(fooVector.begin() + 50, fooVector.end());

    // IS THE LAST LINE THE SAME AS
    fooVector.resize(50);
}

I was wondering, seeing as though the last 50 elements of vector are dangling pointers, would ::erase() and ::resize() do the same thing essentially? I'm guessing that ::resize() would do ::erase() for all old elements after the position of the last element before the ::resize().

Upvotes: 1

Views: 162

Answers (1)

Stack Exchange Broke The Law
Stack Exchange Broke The Law

Reputation: 58868

Yes, erasing the last elements of a vector is equivalent to resizing it.

In both cases the last 50 elements are removed and the vector now has size 50.

Upvotes: 3

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