character array issue

[deepcode]

Trying to make a simple tic tac toe game and I'm stumped, something is not working right.
The grid is drawn easily, but I can't alter the grid for some reason or printf the proper character after getting input. It's probably something very simple and stupid, but its been a long time since doing any programming.

#include <stdio.h>

	/* draw the grid */
void draw_grid(char *grid) {
	printf("\n");
	printf("%c -- %c -- %c\n",grid[0],grid[1],grid[2]);
	printf("%c -- %c -- %c\n",grid[3],grid[4],grid[5]);
	printf("%c -- %c -- %c\n",grid[6],grid[7],grid[8]);
	printf("\n");
}

int get_move(void) {		/* Bugs out if more than 1 character is entered, but have to do this to learn */
	int x = '\0';			/*	ansi-C and not mess with platform specific solutions. */
	int new_line = '\0';
	x = getchar();
	new_line = getchar();
	return x;
}

int main(void) {
	int x = 0;
	char grid[9];
	
		/* initialize the grid */
	for(x = 0; x < 9; x++) {						/*this part works due to the initial grid being printed properly */
		grid[x] = '.';
	}

	while(1) {
		draw_grid(grid);
		x = get_move();
		printf("Value of X: %c\n",x);
		printf("Value of grid[x]: %c",grid[x]);		/* random garbage being printed here instead of '-' character. */
		if(grid[x] != 'X') {						/* this doesn't appear to work at all */
			grid[x] = 'X';
		}
	}
	return 0;
}

[alecodd]

printf("Value of grid[x]: %d",grid[x]); /* random garbage being printed here instead of '-' character. */
if(grid[x] != 'X') { /* this doesn't appear to work at all */

The value of x is THE ASCII value of the character, so for the numbers 0-9 you get actually 48-57, so after you enter 2, for example, you try to access grid[50], which is well beyond the bound of the array.

so you have to convert x by atoi(&x); or do it manually by defining index = x - 48. 48 is the value of the 0 character and so on.

[CommonTater]

int get_move(void) {		
  x = getchar() -'0';
   getchar();
   return x';
}

[deepcode]

Heh, that was incredibly simple. /facepalm.

if(grid[x-'0'] != 'X' || grid[x-'0'] != 'O') {
			grid[x-'0'] = 'X';
		}

Did the trick. Thanks for the help.

[CommonTater]

Heh, that was incredibly simple. /facepalm.

if(grid[x-'0'] != 'X' || grid[x-'0'] != 'O') {
			grid[x-'0'] = 'X';
		}

Did the trick. Thanks for the help.

if you use...

x = getchar() - '0';

and initialize your array properly

char grid[9] = {' '};  // initialize to spaces

your mess abvove becomes...

if (grid[x] == ' ')       // space == unoccupied
  grid[x] = 'X';

One step taken at the beginning eliminates multiple steps at the end.