Re: Save a vector inside a structure.

From:

Carl Barron <cbarron413@adelphia.net>

Newsgroups:

comp.lang.c++.moderated

Date:

Sat, 22 Sep 2007 05:23:46 CST

Message-ID:

<210920072356069505%cbarron413@adelphia.net>

In article <zYidnWBDBsW6zGnbnZ2dneKdnZydnZ2d@giganews.com>, Jensen
Somers <usenet@jsomers.be> wrote:

Hello,

Is it possible to save a vector inside a structure to a file?

Let's say I have the following piece of code:

struct SaveData
{
int first,
int last,
std::vector<int> order;
};

If I write the structure to a binary file and read it out again the data
which should be in the vector is totally corrupt (other variables are
fine).

   think about it:) the vector order has order.size() elements in
contiguous memory so it is simply export the size and then the elements
of order. then reading in the size in a local variable allows order to
be resized() and then the contents read. Not quite a simple posix
read()/write() but if order has any size its almost as fast. further
if you use a streambuf it will be buffered this can be an advantage
inputing the first three ints of the serialized version

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