[Kekeb]

You're treating your grid like it's an array of characters when it's boolean (true or false, not '*', ' ', or any other character).

I suspect your confusion might stem from this line of code,

cout << (grid[y][x] ? '*' : ' ');

which isn't checking to see if the character within the grid is '*' or ' '. The ? operator equates the previous condition and evaluates one of the following expressions depending on the result of the condition (in this case, returning '*' if the grid is true (1) at (y,x) or returning ' ' if the grid is false (0) at (y,x)) The character that's returned by the statement is then passed into cout.

Be careful about extending beyond the bounds of your arrays.