CODEWITHSUNDEEP
c++stl
torayeff
torayeff

Reputation: 9702

C++ vector of fixed size vecors

How can I declare vector of fixed size vectors in C++?

For example:

vector of vectors with N elements.

Not this:

vector<vector<int> > v(N) //declares vector of N vectors

Upvotes: 4

Views: 11351

Answers (3)

Digital_Reality
Digital_Reality

Reputation: 4738

If you wish to have vector of fixed size, most likely you don't need one! Use std::array instead.

But still you insist to have one..

vector<vector<int> > vecOfVec(NumberOfVectors);
for ( int i = 0 ; i < NumberOfVectors; i++ )
   vecOfVec[i].resize(NumberOfElementsInVector);

Upvotes: 1

K.Chen
K.Chen

Reputation: 1286

std::array is your friend here.

http://en.cppreference.com/w/cpp/container/array

For instance, to declare vector of vectors with N elements, you can 

typedef std::array<int, N> N_array;

Then use 

std::vector<N_array>

Upvotes: 6

user2848971
user2848971

Reputation:

You could use std::array:

std::array<int, 10>    myNumbers;

The only down side to this is you can't see how many "active" elements there are, since you don't push/emplace back. You use it like an ordinary( but safe ) array.

Upvotes: 1

Related Questions