how to make a 2d vector in c++

#include <iostream>
#include <vector>

int main() {
    // Step 1: Include necessary header files
    #include <iostream>
    #include <vector>

    // Step 2: Declare a 2D vector using the vector template class
    std::vector<std::vector<int>> twoDVector;

    // Step 3: Specify the dimensions and initialize the 2D vector
    int rows = 3; // Number of rows
    int cols = 4; // Number of columns
    twoDVector.resize(rows, std::vector<int>(cols, 0));

    // Step 4: Access and modify elements of the 2D vector
    twoDVector[0][1] = 5; // Assign a value to an element in the first row, second column

    // Step 5: Print the elements of the 2D vector
    for (int i = 0; i < rows; ++i) {
        for (int j = 0; j < cols; ++j) {
            std::cout << twoDVector[i][j] << " ";
        }
        std::cout << std::endl;
    }

    return 0;
}