How do I access elements in a 2D vector in C++?

How do I access elements in a 2D vector in C++?

You can access elements in a 2D vector using the syntax vector[row][column]. For example, vec[1][2] accesses the element in the second row and third column.

Can you show me an example of initializing a 2D vector?

Sure! You can initialize a 2D vector like this: vector<vector<int>> vec(3, vector<int>(4)); This creates a 3x4 vector.

What if I want to change an element in the vector?

You can change an element by assigning a new value like this: vec[1][2] = 10; This sets the element in the second row and third column to 10.

How do I loop through all elements in a 2D vector?

You can use nested loops. For example:

for(int i = 0; i < vec.size(); i++) {
    for(int j = 0; j < vec[i].size(); j++) {
        cout << vec[i][j] << ' ';
    }
}