On Fri, 26 Mar 1999, Amol Mohite wrote:
# say I have a char *c pointing to an array of 10 bytes.
you mean:
char myarray[10], *c;
c = myarray;
# When i do (int *)c++ (increment before typecast -- forget the brackets for
# nw), and equate it t an int *i then
please re-read what you type. this is full of typos and makes it really
difficult to read. Also include example code as it makes it more clear.
(int *)c++; doesn't do much except make c point at myarray[1] and return
the value typecast as an int (thus returning the character's ascii code).
# *i will return 2nd to fifth bytes as integer. Is this correct ?
no, first make i point to the array. typecasting in that way doesn't
convert the types of the elements in that array. To get the 2nd -> 5th
bytes (elements) as integers you'd have to:
int cnt;
for (cnt = 1; cnt < 5; cnt++)
printf ("%d\n", (int *)(c+cnt)); /* you have to do something with */
/* the typecast variables */
except why bother with pointers to array elements?
for (cnt = 1; cnt < 5; cnt++)
printf ("%d\n", (int *)myarray[cnt]);
# And supose the typecase is beore the incerenent like so :
# ((int *)c)++ then *i will return 5th to 8th byes. is this correct ?
no. that would cast c to an integer and then return the next one, which is
of type char.
# aslo how is exception handling implemented ? Does the processor have
# exception registers ?
what do you mean by exceptions? things like running out of memory and
opening non-existant files, etc? to deal with these the functions that
do the file i/o, memory allocation, whatever. return values that you
check.
# Also if I have allocated a struct liek :
#
# struct {
# int i;
# char b;
# }str;
#
# which is obviously 5 butes large.
not always. it will be
sizeof (int) + sizeof (char)
which on my machine (P233) is 5 bytes. Someone running a Sun or Alpha may have
different sized variables.
# Than whenre will the proceessor allocate the next bit of memory ?
# Directly after the char b byte?
it doesn't matter where it goes. All you need to know, as a C programmer,
is that you have some struct called str which contains an integer and a
character.
Do you own a good C book? (the Kernighan & Ritchie ANSI C Programming Book
is a good one. Ones that mention Turbo C, or other DOS things, aren't - for
Linux programming that is)
--
+++ If at first you don't succeed, you must be a programmer +++
[EMAIL PROTECTED] http://www.users.globalnet.co.uk/~kermit
