what if delete before new?

[SoberGrim]

is it OK to delete a char* before new was called for it?
example:

void read(char*& text)
{
   delete text;
   text = new char[255];
   text = "hello";
}

int main()
{
   char* text;
   read(text);
   printf("%s", text);
   delete text;
}

the reason i write it this way 'cus read() wants to be sure it is given a char[255] pointer, not a char[16] and not an unallocated char*. Deleting "text" and making "text = new char[255]" seems a very easy workaround.
Wouldn't there be any problems with it?

[coder777]

Wouldn't there be any problems with it?

The problem in your case is that you pass an uninitialized pointer which [likely] leads to a crash.

On line 5 you replace the newly allocated memory pointer with a static pointer to a string with the result that delete will crash. Use strcpy instead.

[SoberGrim]

thx mate:)

[andywestken]

void read(char*& text)
{
   delete [] text; // deleting arrays needs delete [] not just delete
   text = new char[255];
   strcpy(text, "hello"); // as was pointed out by coder777
}

int main()
{
   char* text = NULL; // init to NULL (not it's safe to call delete on it!)
   read(text);
   //printf("%s", text); huh - C code?
   cout << test << "\n"; // we are using C++ here!?
   delete [] text; // still need the []
}

It is a good habit to initialize all variables. And esp. here -- init-ing text to NULL makes it safe to call delete [] in it.

Andy