Re: Returning an array -- help needed

From:
Sam <sam@email-scan.com>
Newsgroups:
comp.lang.c++
Date:
Fri, 12 Dec 2008 20:13:34 -0600
Message-ID:
<cone.1229134413.789714.28243.500@commodore.email-scan.com>
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Abhayks writes:

Hi,
I am retuning to "C" after a long time and my basics are shatterred.
Not sure where I am making the mistake.
Please help.

#include<stdio.h>
#include<stdlib.h>

void foo( char ** ptr)
{
  int i;
   *ptr = malloc(255); // allocate some memory
   // strcpy( *ptr, "Hello World");
   for( i=0; i<5; i++)
     {
       *ptr[i]='a';


(*ptr)[i]='a';

     }


(*ptr)[i]=0;

}

int main()
{
    char *ptr = 0;
    // call function with a pointer to pointer
    foo(&ptr );
    printf("%s\n", ptr);
    // free up the memory
    free(ptr);
    return 0;
}

Please advise why this is not working?


1) Operator precedence. [] carries higher precedence than the unary *
operator.

2) The string must be zero-terminated. malloc does not clear allocated
memory.

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