尝试/捕获丢失的向量下标超出范围（调试断言失败）

Question

I have some code, where I'm using std::forward_list
Part of my code tests for vector subscripts being out of range, as well as if the element in the vector has certain properties (in this case, is not -1).
When I have just the first or second node of the list, it works fine and I can catch the error, as that's just a normal part of the program. However, on the next loop around, when I have 3 elements in the list, I get the vector subscript out of range debug assertion, and it isn't caught by my try/catch . Is there a different technique I must use to resolve this error?
Here's a snippet of the code, where it's problematic:

  for(int i = 0; i < 8; i++)
        {
            if(curr->moves[i].at(0) >= 0 && curr->moves[i].at(1) >= 0)
            {
                next->setPos(curr->moves[i].at(0),curr->moves[i].at(1)); //just sets values of a vector
                next->setMoves(); //sets values of a 2d vector
                for(int j = 0; j < 8; j++)
                {
                    try{if(board.kBoard[next->moves[i].at(0)][next->moves[i].at(1)] != -1)  //the debug assertion is thrown here, but I cannot catch it
                            next->moves[i].at(2) = 1;}
                    catch(out_of_range const &err)
                        {next->moves[i].at(2) = 1;}
                }
            ...
          }
     }

I've commented where the issue occurs. You'll (at least on my screen) have to scroll to the right to see it. I believe that, potentially, I can use another catch statement, but I don't know which error to use, given that I'm already using out_of_range , which normally would handle this issue. A screenshot of what the error looks like when it's thrown is this . To be completely clear, the issue occurs at try{if(board.kBoard[next->moves[i].at(0)][next->moves[i].at(1) != -1) , where I have commented. It doesn't go to the catch statement at all, I think because it's using _DEBUG_ERROR()

Answer 1

While, theoretically, a try/catch statement could catch the error here, it isn't wise to intentionally cause errors as part of an algorithm; try/catch should be used to report when errors happen. In this case, I should have used:

if(next->moves[i].at(0) >= 0 && next->moves[i].at(1) >= 0) //1
    if(board.kBoard[next->moves[i].at(0)][next->moves[i].at(1)] != -1) //2
        next->moves[i].at(2) = 1; //3
else
    next->moves[i].at(2) = 1; //3

This allows me to check if the subscript is out of range (1), check if an element of the board is not -1 (2), and set moves[i].at(2) to 1, in those cases (3).
This avoids any out_of_range errors, obviating the need for try/catch entirely.