ORIGINAL CODE STRIPPED TO BARE MINIMUM:

char get_credit (void)
{
    char test_string[]=3D"Your balance is =A34.38.";
    char *pnd_point;
    char *dec_point;
    int length;
    strcpy (rx_array,test_string);
    pnd_point =3Dstrchr (rx_array,'=A3');
    dec_point =3Dstrchr (rx_array,0x2E);
    length =3D(pnd_point - dec_point); // line 244
}


First: It _is_ perfectly legal to subtract one pointer from another in ANSI =

"C", if:

1) The two pointers are pointers to the same type, and
2) They both both into, or just beyond, the same array.

You have met both conditions.

However, I am sure you made a mistake: 'dec_point' will be greater than =

'pnd_point', so when you do your subtraction you will get 'length=3D-2". I =
am =

guessing that perhaps this is your issue, but I am not sure how the compile=
r =

could tell.

Alternatively, you may have a broken compiler that just doesn't understand =

pointer subtraction.

This should work, and be quite efficient

credit_pnd =3D 0;
credit_pence =3D 0;
char const *p =3D strchr(rx_array,'=A3');
while ( *p !=3D '.' )
{
    credit_pnd *=3D 10;
    credit_pnd +=3D *p - '0';
    ++p;
}
++p;
while ( *p !=3D 0 )
{
    credit_pence *=3D 10;
    credit_pence +=3D *p - '0';
    ++p;
}

Alternatively:

pnd_point =3Dstrchr (rx_array,'=A3');
dec_point =3Dstrchr (rx_array,0x2E);
*dec_point =3D 0;
credit_pnd =3D atoi( pnd_point+1);
credit_pence =3D atoi(dec_point+1);

Or even:

char *p;

p =3D strchr(rx_array,0x2E);
credit_pence =3D atoi(p+1);
*p=3D0;
p =3D strchr(rx_array,'=A3');
credit_pnd =3D atoi(p+1);

[ you can reuse the pointer variable ]
--- Bob Ammerman
RAm Systems


-- =

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