how to allocate vector if the size is a variable

[sawfish]

The size of this vector is large, read by configfile.

int j;
std::vector<double> *p = new std::vector<double> [j];

gcc pass, but run in segment fault.
how?

[Bazzy]

You are creating a dynamic array of vectors, try something like this:

int j = /*Some Value*/ ;
std::vector<double> p( j );

http://www.cplusplus.com/reference/stl/vector/vector.html

[sawfish]

thanks, blush.

[kempofighter]

Of course, the value used to initialize the vector must have an actual value. Using an uninitialized integer to construct the vector isn't a good idea. The OP might think this obvious but other beginners might someday find this thread and read it. I agree with Bazzy's point that operator new was not needed here at all. I'd just like to see in the example that j has to be filled with a meaningful value first.

[Bazzy]

Edited my post above