Question

I have a vector of floats, defined by:

std::vector<float>* MyVec;

and I was filling this inside a for loop later with:

MyVec->push_back(somevalue)

and I was getting a seg fault. In order to try and find out what was going on I commented out the push_back line and I still saw a seg fault, and when it seg faulted the size of MyVec was 490618047.

Is there perhaps something I have forgotten to do with this vector, and how is it getting filled by such a huge number without any entries being entered into the vector?

Thanks in advance.

Answer 1

You’ve not allocated memory:

std::vector<float>* MyVec = new std::vector<float>();

Because MyVec is a pointer to std::vector<float>, you’ve to do the above, before using MyVec.

Also, don’t forget to deallocate the memory, once you’re done with MyVec:

delete MyVec;

Apart from that, I think, you don’t need a pointer to begin with; if so, then you should do the following instead of declaring a pointer:

std::vector<float> MyVec; //it is NOT a pointer.

And use it as:

MyVec.push_back(someFloatValue);