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[c++] How to initialize a vector of vectors on a struct?

If I have a NxN matrix

vector< vector<int> > A;

How should I initialize it?

I've tried with no success:

 A = new vector(dimension);

neither:

 A = new vector(dimension,vector<int>(dimension));

This question is related to c++ vector

The answer is

You use new to perform dynamic allocation. It returns a pointer that points to the dynamically allocated object.

You have no reason to use new, since A is an automatic variable. You can simply initialise A using its constructor:

vector<vector<int> > A(dimension, vector<int>(dimension));

Like this:

#include <vector>

// ...

std::vector<std::vector<int>> A(dimension, std::vector<int>(dimension));

(Pre-C++11 you need to leave whitespace between the angled brackets.)

Source: Stackoverflow.com

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