C++：编译向量模板 class 时出现段错误

Question

I'm learning C++ and going through and exercise of creating a custom vector template class, which looks like

template<class T> class Vector
{
private:
    std::vector<T> mData; // data stored in vector
    int mSize; // size of vector
public:
// Constructor
    Vector(int size)
    {
        assert(size > 0);

        mSize = size;
        //std::vector<T> mData;
        mData.resize(mSize);
        for (int i = 0; i < mSize; i++)
        {
            //mData.push_back(0);
            mData[i] = 0;
        }
    }
// Get/set values
    T& operator[](int i)
    {
        assert(i >= 0 && i < mSize);
        return mData[i];
    }

    T const& operator[] (int i)const
    {
        assert(i >= 0 && i < mSize);
        return mData[i];
    }
...
}

I'm trying to overload the unary - operator by doing:

public:
    Vector operator-() const
    {
        Vector v(mSize);
        for (int i = 0; i < mSize; i++)
        {
            v[i] = 0 - mData[i];
        }
        return v;
    }

but this produces a segfault when compiling (with no futher explanation). I have multiple other similiar functions in the template which seem to work. In another template for a matrix class, I also have:

public:
    Matrix operator-() const // unary -
    {
        Matrix mat(mNumRows, mNumCols);
        for (int i = 0; i < mNumRows; i++)
        {
            for (int j = 0; j < mNumCols; j++)
            {
                mat(i,j) = -mData[i*mNumCols + j];
            }
        }
        return mat;
    }

which produces no errors. I am not very familiar with memory issues yet. Is the whole syntax wrong and am I just lucky that the matrix function produces no errors?

Answer 1

Error was not during compiling but running