I have read other similar posts but I just don't understand what I've done wrong. I think my declaration of the vectors is correct. I even tried to declare without size but even that isn't working.What is wrong??
 My code is:

```
#include <vector> 
#include <string>
#include <sstream>
#include <fstream>
#include <cmath>

using namespace std;

vector<string> v2(5, "null");
vector< vector<string> > v2d2(20,v2);

class Attribute //attribute and entropy calculation
{
    vector<string> name(5); //error in these 2 lines
    vector<int> val(5,0);
    public:
    Attribute(){}

int total,T,F;

};  

int main()
{  
Attribute attributes;
return 0;
}

```