Index exceeds matrix dimensions error?

Hello everyone, my code is giving me the error "Index exceeds matrix dimensions. Error in queens (line 11). if test_board(row,col) == 0"

Im trying to attempt backtracking but cant even get passed looping through my array to place queens because of this error.

Any help would be appreciated, thanks!

function [queens] = queens(size)

test_board = zeros(size,size);
final_board = zeros(size,size);
row = 1; col = 1;
queen_counter = 0;

%Loop until "size" number of queens have been successfully placed
while (queen_counter < size)
    %Find first safe space and place queen
    if test_board(row,col) == 0
        test_board(row,col) = 1;
        final_board(row,col) = 1;
        %Attacking the row and column in which the queen was placed
        test_board(:,col) = 8;
        test_board(row,:) = 8;

          %Iterate through using temporary variables to keep real
          %row and column element in place
          temp_row = row;
          temp_col = col;
          %Attacking lower diagonal
          while (temp_col < size && temp_row < size)
              temp_row = temp_row + 1;
              temp_col = temp_col + 1;
              test_board(temp_row,temp_col) = 8;
          end

          temp_row = row;
          temp_col = col;
          %Attacking lower diagonal
          while (temp_col < size && temp_row > 1)
              temp_row = temp_row - 1;
              temp_col = temp_col + 1;
              test_board(temp_row,temp_col) = 8;
          end
          %Move to next column after successful queen placement
          col = col + 1;

          queen_counter = queen_counter + 1;

      %Move down one in column if first space isn't safe    
      else
          row = row + 1;
      end
  end
  disp(test_board); disp(final_board);
  end

Answer 1

[Image Analyst]

DO NOT use size as the name of your variable. It's the name of a vitally important built-in function, that you just overwrote.

Whatever you passed in for size, in your loop either row or column is greater than that, so it throws an error.