# 2D vectors array.......

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• 05-30-2011
zamzamation
2D vectors array.......
Hello everyone,
I need to make a constructor that initialize a 2d vector array by zeros or nulls......
how can i do that ._.
tried nested loops like in 2d arrays but failed
should i use push_back?or is there a way i can do this without it?
• 05-30-2011
phantomotap
What have you tried?

Soma
• 05-30-2011
ManyTimes
Hello, as phantomotap says: tried anything? Show the code.

std::vector can be initialized just when you are creating it, like this:
Code:

```//Creates 2D vector of size 10 and the 0 in the line below defines the default size. std::vector<std::vector <int>> Storage(10, std::vector<int>(10, 0));```
If you define a vector like this (with no default value):
std::vector<std::vector <int>> Storage(10, std::vector<int>(10));
Then initialize it through a loop with another inner loop:
Code:

```int initvalue = 0;         for(int i = 0; i < 10; i++)         {                 for(int ii =0; ii < 10; ii++)                 {                         Storage[ii][i] = initvalue;                        }         }```
Is this all you are trying to do? You can use push.back if you want.
Or are you trying to create a 2D vector by yourself, something along these lines:
Code:

```class Vec2D {     private:       int v[2];     public:       Vec2D(int x, int y);       //etc... }```
• 05-30-2011
zamzamation
thx alot on the replies
this is the last thing i did and it doesn't show any errors anymore but i don't know is this even correct or not -_-" "new to programming"

Code:

```protected:         char w;         int x,y;         int i,j;         vector<vector<char> > Vec(int i, vector<char>(int i,int j)); public:         rand_m_tst()         {                 w='\$';                 x=0;                 y=0;                 i=20;                 j=0;                 vector<vector<char>> Vec(i,vector<char>(i,j));                 for(int f=0;f<20;f++)                 {                         for(int j=0;j<20;j++)                                 Vec[f][j]=NULL;                 }         };```
the 2d vector in protected area is useless now right? -_-"