resize two dimensional vector c++

To resize a two-dimensional vector in C++, you can follow these steps:

1. Declare a two-dimensional vector with a specific size or initialize it with some values.
2. Use the resize() function to change the size of the vector to the desired dimensions.
3. Access the elements of the resized vector using double indexing.

Here's an example of how you can resize a two-dimensional vector in C++:

#include <iostream>
#include <vector>

int main() {
    // Step 1: Declare a 2D vector and initialize it
    std::vector<std::vector<int>> twoDVector = {{1, 2, 3}, {4, 5, 6}, {7, 8, 9}};

    // Step 2: Resize the 2D vector to a new size
    int newRows = 4;
    int newCols = 5;
    twoDVector.resize(newRows, std::vector<int>(newCols));

    // Step 3: Access the elements of the resized vector
    for (int i = 0; i < newRows; i++) {
        for (int j = 0; j < newCols; j++) {
            std::cout << twoDVector[i][j] << " ";
        }
        std::cout << std::endl;
    }

    return 0;
}

In this example, we first declare and initialize a 2D vector with some values. Then, we use the resize() function to change the size of the vector to a new size. Finally, we access the elements of the resized vector using double indexing and print them to the console.