Is there any way to initialize a multi dimensional array if it is a data member of a class? (Such as in an initializer list)

Question

Initializing multi dimensional arrays within a class definition

Answer 1

Yes, you can initialize it that way.

Answer 2

i didnt know you could place an array in a vector like that, and i was told that the second option vector<vector<>> is extremely inefficient because of the ways vectors store data, is that true?

Answer 3

@Albert Lugo : Yes it is but you can do it if you can't figure out an other way to make your code work.
If you're aiming for fast execution (which is not the case when learning) you can try to use pointers.

Answer 4

inside the constructor of the class

Answer 5

yes but i mean using this sort of syntax int nums[size][size]={{1,2,3} , {1,2,3}} ; rather than filling the array with a loop

Answer 6

If I understand correctly whar you're asking, you can declare a multi dimensional array as a member of a class like any other member. You just need to tell their size.
...
private:
int arr[10][10]; // an array of 10 lines and 10 collumns
...

A good advice I could give you is : try to use the functions introduced by c++ like vectors.

...
private:
vector<int[10]> a1; //an array with dinamic collumn number with 10 lines each
vector< vector<int> > a2; //an array with dinamic collumn number which can have their own number of lines
...

Answer 7

to clarify my original question, what if i had a specific data set which i wanted to place into my multidimensional array using initialization rather than manually adding each value to the array one by one. for example :
class mArray
{
private:
int multi[3][3];

public:
mArray(): multi[ ] [ ] ( {1,2,3} , {1,2,3} ) {}

};

would this type of initialization be at all possible?

Answer 8

thanks for the help buddy!

Answer 9

no problem ;)