define vector of vector in c++ code example

Example: vector of vectors c++

#include <iostream> 
#include <vector> 
using namespace std; 
  
int main() 
{ 
	int n = 5;
	int m = 7;
	//Create a vector containing n vectors of size m and initalize them to 0.
	vector<vector<int>> vec(n, vector<int>(m, 0));

	for (int i = 0; i < vec.size(); i++) //print them out
	{
		for (int j = 0; j < vec[i].size(); j++)
		{
			cout << vec[i][j] << " ";
		}
		cout << endl;
	}
}