Question

I declared a multidimensional array in C, like so:

int arr[4][2];
int length = 0;

But I can apparently add as many elements as I want:

void addStuff(){
    arr[length][0] = someVal;
    arr[length++][1] = someVal;
}

and it doesn’t give any errors. Does this mean I’m corrupting my memory somewhere in no-man’s land? Or is this some feature of C I don’t know about?

Answer 1

If you assign past the array size, you’re definitely corrupting memory somewhere – the program may segfault, or other data may get corrupted, or it may (by accident) behave correctly. There’s no bounds checking by default in C.