Assign array of pointers to array

Question

If I have an array of char pointers and another static array of characters, how do I assign each element of the array of pointers to each element of a static array?

(Trying to break down a problem into a smaller problem.)

Thanks.

   array of pointers                            array of char
    +----+                                           +----+                        
    |    |       ---->                               |    |
    | *  |                                           |  h |
    +----+                                           +----+
    | *  |                                           | i  |
    |    |         ---->                             |    |
    +----+                                           +----+

Answer 1

"If I have an array of char pointers"

char** arr;

"and another static array of characters"

char str[]="Hi there"

"how do I assign each element of the array of pointers to each element of a static array? "

len = strlen(str);
arr = (char **)malloc(sizeof(char *) * len);/*typecasting for C++ */
 if ( arr != NULL)
 {
   for(i=0; i < len; i++)
   {
     arr[i] = (char *)malloc(sizeof (char)); /* typecasting for C++ */
     if ( arr[i] != NULL)
       {
        arr[i] = &str[i];
        }
     else
       {
         /*If you choose to return from here,
          * free allocated memory upto now 
          */
         for(j=0;j<i;j++)
           {
             free(arr[j]);
           }
         free(arr);
         return 1;
       }

   }
 }

Hope it helps.

Answer 2

Aditya's re-submitted your answer. I'm not sure why you alloc'd all the pointers. "If I have an array of char pointers"

char** arr;

"and another static array of characters"

char str[]="Hi there";

"how do I assign each element of the array of pointers to each element of a static array? "

len = strlen(str);
arr = (char **) malloc(sizeof(char *) * len); /*typecasting for C++ */
if ( arr != NULL )
{
  int i=0;
  for(i=0; i < len; i++)
     arr[i]=&str[i];
} else {
   // error handling
}

Of course these pointers are valid only until static str array exists (normally until you exit the statement block). Very error prone, but this was precisely your request.

Answer 3

char **getPointers(char *initArr) {
char **arr;
int len, i;

if(initArr == NULL) return NULL;

/* + 1 for the null terminator */
len = strlen(initArr) + 1;

arr = (char **) malloc(sizeof(char *) * len);

/* since initArr is an array, we know the characters are contiguous in memory,
    so let's trust pointer arithmetic instead of dereferencing references we 
    create */
for(i = 0; i < len; i++) arr[i] = initArr + i;

return initArr;
}

Answer 4

char  chrArr[] = "asd";
char* ptrArr[strlen(chrArr)];

char*  chrPtr = chrArr;
char** ptrPtr = ptrArr;

while (*chrPtr)
    *ptrPtr++ = chrPtr++;

Answer 5

I am improvising Tomi's answer here.
The others are too long for such a question.

char  chrArr[] = "asd";
char* ptrArr[sizeof(chrArr)];
int i;

// A simple assignment loop over 'i' pointers and chars
for (i=0; i< sizeof(chrArr); i++)
    ptrArr[i] = &chrArr[i];
    ---------   ----------
//  pointer =   address of character

Since I used sizeof you get a 4th pointer here that is pointing to the NULL termination character of the string.