如何修改此条件以接受另一种可能性？

Question

Currently, I have this:

printf("%c", board[down][across] == 0 ? 'O' : 'X');

Which means - If the value at this position in the array is 0, display 'O', otherwise display 'X'

How do I modify this so that:

If the value at this position in the array is 0, display 'O', or if the value is 1 then display 'X' or if the value is 2 display '#'?

I understand I can just use if statements and use the printf line multiple times, but is there a better way of doing so, in one line, like above?

Thanks.

Answer 1

Make a function that takes the grid value and returns the char .

Ensure you handle unknown values as you must always return something.

char get_char(int const grid_value)
{
  switch (grid_value)
  {
    case 0:
      return 'O';

    case 1:
      return 'X';

    case 2:
      return '#';

    default:
      return '?';
  }
}

then just

printf("%c", get_char(board[down][across]));

Answer 2

A straightforward way is to add an extra condition:

grid[down][across] == 0 ? 'O' : grid[down][across] == 1 ? 'X' : '#'

This is parsed as

grid[down][across] == 0 ? 'O' : (grid[down][across] == 1 ? 'X' : '#')

So you'll get the desired result that 0 → O , 1 → X and everything else → # .

---

Apparently it's going to be a mess if you want some more values (eg 3, 4, 5 and so on). If you can make some assumption or guarantee about your values, like it will always be non-negative and bounded, you can use an array to hold your characters:

const char LEGEND[] = {'O', 'X', '#'};
// ...
printf("%c", LEGEND[grid[down][across]]);

This has the advantage that you can easily add more values, for example:

const char LEGEND[] = {'O', 'X', '#', '!', '?', '.'};

but of course, it's never bad to check if the value is within the desired range before using it as array indices. So your code should be:

int ind = grid[down][across];
// Assume you're using 3 characters
if (ind < 0 || ind >= 3) {
    puts("Oops!");
    exit(1);
}
printf("%c", LEGEND[ind]);

Answer 3

Create an array with possible values:

char values[3] = {'O', 'X', '#'};

and then simply

printf("%c", values[grid[down][across]]);

Answer 4

You can nest ternary operator.

printf("%c", grid[down][across] == 0 ? 'O' : grid[down][across] == 1 ? 'X' : '#');

But sure don't use such that code in production!