keep getting ascii value where char is expected - c

Question

When a coordinate is selected, it should be replaced with a "~". However, it's being replaced with the ascii value for the ~ instead (126). I tried a few different things, but I always get the 126 instead of the ~. Any ideas?
Thanks for the help!
int board_is_empty(int N, int board[ROWS][COLS])
{
int i = 0, j = 0;
for (i = 0; i < N; i++)
{
for (j = 0; j < N; j++)
{
if (board[i][j] != '~')
{
return 0;
}
}
}
return 1;
}
//updates the board to replace each selected coordinate with a ~.
//returns nothing
void update_board (int board[ROWS][COLS], int row_target, int column_target)
{
board[row_target][column_target] = '~';
}
int main(void)
{
int game_board[ROWS][COLS] = {0};
int rows, columns = 0;
int players_turn = 1, target_column = -1, target_row = -1, value = 0;
int row_selection = 0, column_selection = 0;
int i = 0;
initialize_game_board(game_board);
display_board(game_board);
generate_starting_point(game_board, &rows, &columns);
printf ("\nPlease hit <Enter> to continue.\n");
getchar ();
while (board_is_empty(ROWS, game_board) != 1)
{
select_target (&target_row, &target_column, players_turn);
value += game_board[target_row][target_column];
update_board (game_board, target_row, target_column); //should cause the coordinates at target_row && target_column to be replaced with a ~
display_board(game_board);
}
printf("\n%d", value);
}

Answer 1

'~' is a character and you have declared board as a two dimensional integer array.
so when you write board[row_target][column_target] = '~';
it convert '~' it into integer i.e into its ascii value which is 126
and there for it becomes board[row_target][column_target] = 126
I will suggest make board as two dimensional character array. Hopefully it will solve your problem.
And in case if you want it as integer only then consider 126 as a special no which means '~' by declaring

Answer 2

For storing your coordinates, you are using an integer array. When you execute
board[row_target][column_target] = '~'; tilde's ascii value (126) is assigned to LHS. There is no way you can assign a character to an integer value. I think you should use some special number rather than tilde. If I were you, I would use INT_MIN or INT_MAX.

Answer 3

There isn't a difference between the character '~' and the number 126 as far as the C language is concerned, '~' == 126.
(You used "~" which i would normally use for a string, but i assume you don't actually mean that).
If you want to display a value, you have to use the correct format string. %d is for decimal integers, %c would be for characters (the variable holding the value should also be a char)

Answer 4

In C, chars are just integers. At output time they are represented as characters but internally they hold just the ASCII code of that character.
Since your board is a matrix of int's, when you assign '~' you are effectively assigning the number 126 to a position of the board. If you check that position, the expected result is to get an int equal to 126.
However, if you want to see that value as a character, you can do it by casting that number into a char:
printf("%c", value);
Take a look:
#include <stdio.h>
int main()
{
int i = '~';
char c = '~';
printf("Integer: %d\n", i); /* outputs: 126 */
printf("Char: %c\n", c); /* outputs: ~ */
printf("Integer casted to char: %c\n", i); /* outputs: ~ */
}
That is, your value is right. You just need to get the representation you want. (If you want to be able to store the value 126 in the board and the character ~ at the same time, then you're out of luck because for C they are the same thing -you can use some other value that you know that the board isn't going to hold, like -1 or something like that).
Update:
So, if I didn't get it wrong what you're trying to do is to read numbers from a bidimensional matrix of random integers and mark each one as you go reading them.
If that is what you're trying to achieve, then your idea of using '~' to mark the read positions isn't going to work. What I meant before is that, in C, 126 and the character '~' are the exact same thing. Thus, you won't be able to differentiate those positions in which you have written a '~' character and those ones in which a random 126 is stored by chance.
If you happen to be storing positive integers in your array, then use -1 instead of '~'. That will tell you if the position has been read or not.
If you are storing any possible random integer, then there is nothing you can store in that array that you can use to mark a position as read. In this case a possible solution is to define your array like this:
typedef struct {
int value;
char marked;
} Position;
Position board[ROWS][COLS];
Thus, for each position you can store a value like this:
board[row][col].value = 23123;
And you can mark it as read like this:
board[row][col].marked = 'y';
Just, don't forget to mark the positions as not read (board[row][col].marked = 'n';) while you fill the matrix with random integers.