Accessing a bit array in linked list node

Question

I have a linked list defined as such:

typdef struct _seg
{
    int bits[256];        // # of bits in bits[] array = 256

    struct _seg *next;    // link to the next segment
} seg;

And I was wondering how I can access the bit array inside each node of this list. If it were a regular int variable and the list was called p, I could just do p->bits = 13;. But I don't know how to get to and modify the list in this case. Can someone please help me out?

P.S. (not as important) Does anyone know what the seg; does at the very end?

Here you find the meaning of "typedef": http://stackoverflow.com/a/612350/126125 — Markon, May 03 '13 at 13:54
@Markon Thanks! That makes a lot of sense and makes things a lot easier! — yiwei, May 03 '13 at 13:56
The way you've declared your structure, the `bits` array is an array of ints, so it has `256*sizeof(int)*8` bits. — Caleb, May 03 '13 at 14:05

score 1 · Answer 1 · edited May 03 '13 at 14:18

1

p->bits is an array of 256 integers. You can access it with p->bits[0] = 13.

Or in general p->bits[i] = 13 where 0 <= i < 256.

typdef struct _seg { ...
}seg;

With this you can define a variable of this struct type using seg as

seg SomeName;

No need for struct _seg someName;.

edited May 03 '13 at 14:18

Gui13

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answered May 03 '13 at 13:50

Rohan

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I'm assuming you meant to type `p->bits[0] = 13`. Thanks! – yiwei May 03 '13 at 13:52

score 1 · Answer 2 · answered May 03 '13 at 13:59

To access the nodes in your list, you'll have to use a loop to iterate on all your elements:

seg* p = createList();

seg* current = p; // start at first element
while( current != NULL ){
    for( int i=0; i<256; i++ ) {
        current->bits[i] = 13;  // modify bits inside
    }
    current = current->next; // go to next element in the list
}

Accessing a bit array in linked list node

2 Answers2