Taking in a 2D vector of a string from a user but ends up getting segmentation fault

Question

I am trying to input a 2d vector of string "t" times and make a grid of 2 * 2 size "t" times using C++ and the inputs can be integers 0 to 8 (inclusive) and ".", so i tried using a 2d vector of string but I am getting segmentation fault when accessing any element of a row > 0. I think it's because cin is buffered. Can anyone guide to how to debug this or use any other method.

here's the code inside main

    int t;
    cin>>t;
    while(t--)
    {
        vector<vector<string> > grid(2);
        vector<string> temp(2);
        // vector<vector<char> > grid(2);
        // vector<char> temp(2);
        for(int i = 0; i < 2; i++)
        {
            for(int j = 0; j < 2; j++)
            {
                cout<<j<<" "; //loop is running when *enter* is pressed
                cin>>temp[j];
    
                // cin.get(temp[j]);
            }
            grid[i] = temp;
            temp.clear();
        }
        cout<<"t-> "<<t<<" "<< grid[1][0]<<endl;  //getting segmentation fault here
    }

edit: if I put the vector<string> temp(2) inside first loop then it's working but idk why coz i did use clear() so idk why is this the case.

Answer 1

No, nothing to do with cin being buffered.

The error is here

        temp.clear();

That line changes the size of temp to be zero, so on the next input cin >> temp[j]; you have a vector subscript error because temp has zero size.

Just remove the line temp.clear(); and your code will work.