• kw (10/10) Sep 07 2003 Why is the following not working? (DMD 0.71)
• DeadCow (10/11) Sep 07 2003 You are copying array in the same array as if you do :
• Mike Wynn (4/19) Sep 07 2003 try using
• kw (4/8) Sep 07 2003 Thanks! That worked.
• Daniel Yokomiso (23/35) Sep 07 2003 In D arrays are more than pointers, because they carry length informatio...

kw <kw_member pathlink.com> writes:

Why is the following not working? (DMD 0.71)

int main (char[][] args)
{
char[] s = "12345";

printf("%s --> ", (char *)s);
s = s[0 .. s.length-1]; // I want to strip the last char
printf("%s\n", (char *)s);
return 0;
}

It prints 12345 --> 12345

"DeadCow" <deadcow-remove-this free.fr> writes:

"kw" <kw_member pathlink.com> a écrit dans le message news:
bjgids$1hdv$1 digitaldaemon.com...

 s = s[0 .. s.length-1]; // I want to strip the last char

You are copying array in the same array as if you do :

s[0] = s[0];
s[1] = s[1];
...
s[s.length-1] = s[s.length-1];

Try it :

s.length--;

-- Nicolas Repiquet

Mike Wynn <mike l8night.co.uk> writes:

kw wrote:
 Why is the following not working? (DMD 0.71)
 
 int main (char[][] args)
 {
 char[] s = "12345";
 
 printf("%s --> ", (char *)s);
 s = s[0 .. s.length-1]; // I want to strip the last char
 printf("%s\n", (char *)s);
 return 0;
 }
 
 It prints 12345 --> 12345
 
 

try using
printf( "%.*s", s );   slices are not null terminated s[0..1] will still 
  printf %s as s[0] ... \0 (if you get my meaning)

kw <kw_member pathlink.com> writes:

Not working:
 printf("%s\n", (char *)s);


try using
printf( "%.*s", s );   slices are not null terminated s[0..1] will still 
  printf %s as s[0] ... \0 (if you get my meaning)

Thanks! That worked.
I few warnings for things that are not very intuitive for C programmers would be
a nice addition.

"Daniel Yokomiso" <daniel_yokomiso yahoo.com.br> writes:

"kw" <kw_member pathlink.com> escreveu na mensagem
news:bjgids$1hdv$1 digitaldaemon.com...
 Why is the following not working? (DMD 0.71)

 int main (char[][] args)
 {
 char[] s = "12345";

 printf("%s --> ", (char *)s);
 s = s[0 .. s.length-1]; // I want to strip the last char
 printf("%s\n", (char *)s);
 return 0;
 }

 It prints 12345 --> 12345


In D arrays are more than pointers, because they carry length information
too. But String literals have a additional invisible \0 in the end. So when
you say:


 printf("%s --> ", (char *)s);


You are treating the address/length pair that represents the array as a
"char*", so the length info is lost, but the invisible \0 at the end of
"12345" is used to terminate the string inside "printf".
When you slice the array, you just create a new address/length pair, so the
sliced variable


 s = s[0 .. s.length-1]; // I want to strip the last char


Points to the original "12345\0" array, when used as an array it'll give a
reduced length. But when you cast it to "char*" the printf will find the \0
only after "5". So you either use "%.*s" instead (that handle "char[]"
properly) or use the "toStringz" function from Phobos, that'll give a
"char*" with the \0 at the end, so "toStringz(s[0 .. s.length-1])" will
return a "char*" pointing a memory location containing "1234\0".

    Best regards,
    Daniel Yokomiso.

"Lord save me from your followers."


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