Segmentation fault when inserting into the stringstream

Question

I get a segmentation fault, but I don't use any pointers. It's being happened when I insert into the stringstream.

std::string Relations::toString()
{
    std::stringstream restring;
    restring << ID << "(";

    restring << reList[0]; // segmentation fault

    for (int c = 1; c < reList.size(); c++)
    {
        restring << "," << reList[c];
    }

    restring << ")";
    return restring.str();
}

Well, to start with, there's going to be an obvious crash if the vector is empty, or has only one element. — Sam Varshavchik, Sep 26 '17 at 21:04
You don't seem to check whether `reList` has sufficient size before accessing second item at `reList[1];`. Also item indexes in C/C++ typically start from 0. — user7860670, Sep 26 '17 at 21:05
Could also be a bad `this` pointer. Lot of possibilities. [mcve] please. — user4581301, Sep 26 '17 at 21:10
are you sure you mean [1] and not [0]? Does the list have any entries in it. use reList.at(x) instead of [x]. you will get better diagnostic — pm100, Sep 26 '17 at 21:21

boriaz50 · Answer 1 · 2017-10-07T10:28:50.077

0

Before accessing the reList[0] you have to check it exists.

std::string Relations::toString()
{
    std::stringstream restring;
    restring << ID << "(";

    if (reList.size() > 0)
    {
        restring << reList[0];
        for (std::size_t i = 1; i < reList.size(); ++i)
        {
            restring << "," << reList[i];
        }
    }

    restring << ")";
    return restring.str();
}

edited Oct 07 '17 at 10:28

answered Sep 26 '17 at 21:13

boriaz50

860
4
17

score 0 · Answer 2 · answered Sep 26 '17 at 23:05

0

I answered my own question, making me realize that this was a dumb question. I was using this class wrong in another class and there was nothing going into my vector. Therefore, I was trying to access the empty vector.

answered Sep 26 '17 at 23:05

JKdub

9
2

Segmentation fault when inserting into the stringstream

2 Answers2