exc_bad_access（代码= 2地址= 0x0）

Question

I am new to this, trying to make an Minesweeper iphone app

i used a IBButton to Reset mine fields which is a 2 by 2 matrix of a struct

- (IBAction) Reset {
    for (int x = 0 ; x < 10 ; x ++) {
       for (int y = 0 ; y < 10 ; y++ ) {
           f[x][y]->isOpen = NO;
           f[x][y]->display = 0; //Going to make a search function for finding Number of mines next to it
           int random = arc4random()%10;
           if (random < 2) {
               f[x][y]->isMine = YES;
           } else {
               f[x][y]->isMine = NO;
           }
        }
    }

so i get the the error at the very first line of my for loop f[x][y]->....

what did i do wrong here?

/edit

This is how i declared my f

struct feild *f[10][10];
struct feild{
    bool isOpen;
    bool isMine;
    int display;
}

Answer 1

You haven't allocated any space for f, so f[x][y] will just contain junk memory and then the ->isOpen = NO access will blow up.

you need to do something like

for (int i = 0; i < 10; i++) {
    for (int j = 0; j < 10; j++) {
        f[i][j] = malloc(sizeof(struct feild));
    }
 }

before your code.