Re[2]: [Dev-C++] using char* as bitfield

[Per W. <pw...@ia...>]

Yes, it is possible to do with char*

char* alloc_bits(unsigned bits) {
    char *bits;
    unsigned size;
    size =3D (bits+7)/8;
    bits =3D malloc(size);
    if (bits) memset(bits,0,size);
    return bits;
}

void set_bit(char* bits,unsigned bit) {
    array[bit/8] |=3D 1 << (bit&3);
}

char *mybits;

mybits =3D alloc_bits(1000);
if (mybits) set_bit(mybits,117);

/Per W

On Mon, 29 Sep 2003, [ISO-8859-15] Christian Sch=E4fer wrote:

> hi David,
>
> > Do you know how many bits you will need at compile time?
> yes, I do.
>
> > If you then use a bitset. It is part of the STL.
> I should have said, that I am doing this in c not in c++.
>
> > If you don't then you can use vector<bool> and hope your
> > compiler vendor
> > optimized it for space.
>
> it should be possible to use a char*, right?
>
>
>
> gruss
> /Christian                   mailto:ca...@kr...
>
> ---
>
>
> I propose that the following character sequence for joke markers:
>
> :-)
>
>                              19-Sep-82 11:44    Scott E  Fahlman
>
>
>
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