Can I access a pointer as a 2D array in C?

Question

Lets' say I have a pointer to int:

int *p = somefunc();

I know it points to 25 ints, logically arranged in a 5x5 grid. I can access an element with this:

p[y*5+x]

or this:

*(p+y*5+x)

Is there a way access it as a 2D array?

a[y][x]

melpomene · Accepted Answer · 2015-07-28 12:31:36Z

8

Yes:

int (*a)[5] = (int (*)[5])p;

answered Jul 28, 2015 at 12:31

melpomene

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2 Comments

Is it not possible without explicit casting?

@TorKlingberg As far as I know, no.

Senua · Accepted Answer · 2015-07-28 12:37:21Z

1

I'd do a simple function to do it :

int at(int * p, int x, int y)
{
    return p[y*5+x]
}

You can add another parameter for less specific width of table (i.e. other that 5), but that's how I usually do it.

answered Jul 28, 2015 at 12:37

Senua

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