Re: Another question about multidimensional vectors

From:
Juha Nieminen <nospam@thanks.invalid>
Newsgroups:
comp.lang.c++
Date:
Sun, 28 Oct 2007 12:32:25 +0200
Message-ID:
<47246618$0$3519$39db0f71@news.song.fi>
Markus Pitha wrote:

How can I push_back() a vector which contains ints to a vector?


  Just resize the vector and push back the int into the first vector.
For example:

values.resize(1); // now it has 1 int-vector inside it.
values[0].push_back(35); // Pushes 35 into the first vector.

  If you want to *literally* push a vector of ints into 'values', you
can literally do that too. For example:

std::vector<int> aVector(1, 35); // initialized to have 1 value, 35
values.push_back(aVector);

I tried it in a different way like:

vector<int> xAxis;
vector<xAxis> yAxis;


  I don't really understand what is it that you tried to accomplish
with that. If what you want is to create an x*y double-vector, you can
do it like this:

std::vector<std::vector<int> > values(xSize, std::vector<int>(ySize));

  Now 'values' will be a vector with xSize vectors inside it, and each
one of these will have ySize ints inside them. Then you can simply
access the values like values[2][3].

Why do
I actually have to resize them although vectors are dynamic types?


  You have to resize them *because* they are dynamic types, not *although*.

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