how to get size of 2d vector in c++
#include <iostream>
#include <vector>
int main() {
std::vector<std::vector<int>> matrix = {
{1, 2, 3},
{4, 5, 6},
{7, 8, 9}
};
int rows = matrix.size();
int cols = matrix[0].size();
std::cout << "Number of rows: " << rows << std::endl;
std::cout << "Number of columns: " << cols << std::endl;
return 0;
}