Good afternoon everybody,

I have a problem with printing the pointer array

char *name[] = {"January", "February", "March", "April"};

What I want to do is print the names "January", "February", "March" and
"April"
and I just can't get it done the way I want it. I have several solutions
which are not very satisfactory or just plain wrong. For example, I have
used
this:

while (name[0] <= name[3])
{
   while (*name[0] != '\0')
      printf ("%c", *(name[0])++);
   printf ("\n");
   ++name[0];

which makes the false assumption that "January" is stored in memory before
"February" etc (it works on quite a number of machines though). I also have
appended a "1" to the array, so that I can use the code

while (*(name[0]) != '1')
{
   while (*(name[0]) != '\0')
      printf ("%c", *(name[0]++));
   printf ("\n");
   ++name[0];

which is extremely ugly. The problem looks a little like the argv and argc
manipulation (page 117 of K&R, the page where I got stuck with this
problem),
but the advantage there is that a counter-controlled loop can be written,
because we have an argc. Is there some way equal to that approach but
without
the use of a special counter that keeps track of the number of arguments?
I'm not
looking for a simple for-loop.

Any help or pointers to get this annoying problem out of the way would be
appreciated.

Cordially,

Casper van Eersel

: Good afternoon everybody,

: I have a problem with printing the pointer array

: char *name[] = {"January", "February", "March", "April"};

: What I want to do is print the names "January", "February", "March" and
: "April"
: and I just can't get it done the way I want it. I have several solutions
: which are not very satisfactory or just plain wrong. For example, I have
: used
: this:

: while (name[0] <= name[3])
: {
:    while (*name[0] != '\0')
:       printf ("%c", *(name[0])++);
:    printf ("\n");
:    ++name[0];
: }

: which makes the false assumption that "January" is stored in memory before
: "February" etc (it works on quite a number of machines though). I also have
: appended a "1" to the array, so that I can use the code

: while (*(name[0]) != '1')
: {
:    while (*(name[0]) != '\0')
:       printf ("%c", *(name[0]++));
:    printf ("\n");
:    ++name[0];
: }

: which is extremely ugly. The problem looks a little like the argv and argc
: manipulation (page 117 of K&R, the page where I got stuck with this
: problem),
: but the advantage there is that a counter-controlled loop can be written,
: because we have an argc. Is there some way equal to that approach but
: without
: the use of a special counter that keeps track of the number of arguments?
: I'm not
: looking for a simple for-loop.

You can either use a terminating value, such as NULL, or a counter.
The conventional approach would be:
int j;
for (j = 0; j < sizeof(name)/sizeof(name[0]); j++)
   printf("%s\n", name[j]);

Will

What you want is something like the following:

#include <stdio.h>

int main( void )
{
    char *name[] = {"January", "February", "March", "April"};
    int i;

    for ( i = 0; i < sizeof name / sizeof name[ 0 ]; ++i )
        puts( name[ i ] );

    return 0;

If you were to have the following statement:

char text[] = "Hello World";

then sizeof (text) would be 12.  The array has 11 characters and the
terminating NUL character.  In your example, we will assume a pointer is 4
bytes.  "Name" is an array of pointers.  In this particular case, it is an
array of 4 pointers that are 4-bytes each, i.e. 16 bytes.  "Name[ 0 ]"
contains one pointer which (as I've stated) is 4 bytes.  Therefore, sizeof
name / sizeof name[ 0 ] is the same as 16 / 4 which is 4.  Some
reinterpretations of my loop are:

for ( i = 0; i < 16 / 4; ++i )
    puts( name[ i ] );

and

for ( i = 0; i < 4; ++i )
    puts( name[ i ] );

You probably don't have to worry much about what looks like constant
division because a decent optimizing compiler will automatically compute
"sizeof name / sizeof name[ 0 ]" to be 4 only once (again assuming the size
of your pointers are 4 bytes).

--
Increase the Peace!
Charles LaCour

How about:

char *name[] = { "one", "two", "three", 0 };  /* Note trailing NULL */
int i;
for (i = 0; name[i]; i++)
    printf("%s", name[i]);

Why aren't you looking for a simple for loop?
Simple is a good thing.