Question

char *substring(char *text, int position, int length)
{
   int i, j=0;
   char *temp ;

   for(i=position-1; i<position+length-1; i++)
   {
     temp[j++] = text[i];
   }
   temp[j] = '\0';

   return temp;
}

Hi What is the error in the following code.. I am trying to run this on Fedora Machine.. And its giving me a run-time error “Segmentation Fault”. What is this error all about.. and why is it giving this error..

Thanks..

Answer 1

You need to allocate memory for temp – currently it’s just a dangling pointer. You can use malloc for this but note that the caller will need to ensure that this storage is subsequently freed.

For example:

char *substring(const char *text, int position, int length)
{
   char *temp = malloc(length + 1);
   int i, j;

   for (i = position, j = 0; i < position + length; i++, j++)
   {
       temp[j] = text[i];
   }
   temp[j] = '\0';

   return temp;
}