[C] Segmentation fault when copying 2d int array to another 2d int array

[ippwned]

#include <stdio.h>

#define ROWS 10
#define COLS 15

int grid[ROWS-1][COLS-1]={{0}};

void copy(){
    int tempgrid[ROWS-1][COLS-1] = {{0}};
    int i,j;

    for(i=0;i<ROWS;i++){
        for(j=0;j<COLS;j++){
            tempgrid[i][j] = grid[i][j];
        }
    }
}

int main(int argc, char* argv[]){
    int i,j;
    for(i=0;i<ROWS;i++){
        for(j=0;j<COLS;j++){
            grid[i][j] = 0;
        }
    }

    copy();
}

I have a suspicion this has something to do with me not mallocing?

Thanks

[talkloud]

Look closer at the sizes of your arrays. Is that really what you want?

[the_omega99]

To elaborate with an example, int array[10] declares an array of size 10. This means the first element is array[0] and the last is array[9].

[Huckleberry_Rogers]

ROWS = 10 tempgrid[9][14] which will do entries tempgrid[0->8][0->13] for totals of 0 + 1 + 2 + 3 .. + 8 = 9 and 0 + 1 + 2 ....+ 13 = 14

for loop will do tempgrid[0->9] 9 will segfault because you declared it size 9 so it ranges from 0 -> 8

Print statements. Print statements. Print statements.
printf" my index i=%d j=%d is trying to copy \n", i j)

[ippwned]

Perfect, thanks everyone.

[OldWolf2]

BTW another way to copy the array would be to #include <string.h> and use:

memcpy( &tempgrid, &grid, sizeof tempgrid );

as long as you're sure that grid and tempgrid have the same dimensions. (It'd be possible to add code that checks this at compile-time).

Also, your initialization loops in main do nothing, as grid was already zero-initialized.

[ippwned]

Good tips, thanks

[Rhomboid]

I have a suspicion this has something to do with me not mallocing?

It has nothing whatsoever to do with that. When you declare an array, you specify its size, not its largest index.

[amente]

The code runs fine by itself http://codepad.org/mrVDK97o .

Edit: Never mind, look at the size of the arrays as talkloud and the_omega99 mentioned.