Looping through std::vector and deleting elements results in out of range exception

Asked Sep 19 '17 at 13:21

Active Sep 19 '17 at 13:29

Viewed 76 times

I have a std::vector array (vectorArr) of objects. Have 2 threads, 1 push objects vectorArr array and other work with them. Some objects must be deleted from it when I end work with them. So I just add such objects index number to other std::vector<int> (DeleteList) and then iterate over it and erase objects from vectorArr by the saved index, but some times I'm getting an out of range exception. I don't understand why that happens.

std::vector<int> DeleteList;
int index = 0;
for (auto &data : vectorArr)
{
    if (data.frames < 150) {
        data.frames++;
        //some code here
    }
    else DeleteList.push_back(index);
    index++;
}

if (DeleteList.empty())
    return;

for (auto &dIndex : DeleteList) {
    if (dIndex < vectorArr.size())
        vectorArr.erase(vectorArr.cbegin() + dIndex); // out of range exception
}
DeleteList.clear();

edited Sep 19 '17 at 13:29

Andre Kampling

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asked Sep 19 '17 at 13:21

SLI

3

Please post a [mcve]. – wally Sep 19 '17 at 13:22
2

The vector shrinks when you erase from it. – molbdnilo Sep 19 '17 at 13:25
ah, i get it. Thank you. @molbdnilo – SLI Sep 19 '17 at 13:27
1

You might want to [look up the *erase-remove idiom*](https://en.wikipedia.org/wiki/Erase%E2%80%93remove_idiom), which is an easy and efficient way to delete multiple elements from a vector. – ComicSansMS Sep 19 '17 at 13:29
3

If you delete backward this could work, but anyway erase-remove idiom is more efficient. – Slava Sep 19 '17 at 13:37

Looping through std::vector and deleting elements results in out of range exception

0 Answers0