c++ - How to implement 2D vector array?

Question

I'm using the vector class in the STL library for the first time. How should I add to a specific row of the vector array?

struct x{
     vector <vector <int> > v;
     int row;
 };

vector< int* > my ints;
int add;

if i wanted to add to first row of v with the first pointer of integers, could I do

myints[0]->v[myints[0]->row].push_back(add);

Is this method fine to create a 2 D vector of vector ints where each row could potentially be of different length (i.e. have a different number of columns)?

Answer 1

I'm not exactly sure what the problem is, as your example code has several errors and doesn't really make it clear what you're trying to do. But here's how you add to a specific row of a 2D vector:

// declare 2D vector
vector< vector<int> > myVector;
// make new row (arbitrary example)
vector<int> myRow(1,5);
myVector.push_back(myRow);
// add element to row
myVector[0].push_back(1);

Does this answer your question? If not, could you try to be more specific as to what you are having trouble with?