How do I read a text file into a 2D vector?

I have to read a text file which has rows and columns into a vector. The text file could be of any size. One example of text file:

T,T,T,F,T
T,T,T,T,T
T,T,T,T,T
T,T,T,T,T
T,T,T,T,T
T,T,T,T,T
T,T,T,T,T

Now, how do I upload this text file on to a 2D vector?

so far, I know I have to use a vector of vectors (2d vector) and so I initialized it like this:

vector<vector<char> > forest;

I don't know how to move forward from here. I would assume I must use a nested for loop but I don't have much practice with 2d vectors.

I also was thinking about using getline and reading each line as a string or using the .get function and treat each character as a char within a while loop?

You can use getline to read the file line by line into strings. For each string you read, iterate over its characters to build row vectors to populate your forest:

#include <fstream>
#include <iostream>
#include <string>
#include <vector>

int main() {
    std::string line;
    std::ifstream infile("file.txt");
    std::vector<std::vector<char> > forest;

    while (std::getline(infile, line)) {
        std::vector<char> row;

        for (char &c : line) {
            if (c != ',') {
                row.push_back(c);
            }
        }

        forest.push_back(row);
    }

    for (std::vector<char> &row : forest) {
        for (char &c : row) {
            std::cout << c << ' ';
        }

        std::cout << '\n';
    }

    return 0;
}

Output:

T T T F T
T T T T T
T T T T T
T T T T T
T T T T T
T T T T T
T T T T T