delete new char[] correctly ?

[vincentThorpe]

Hi padawan here So do l have this situacion. l call a function twice that returns a c-string, and l save into the same char* pointer (* c_string). but is correct to delete that (* c_string) before assigning the return value again to foo() ?. Because if l dont part of the content remains, when l stepped in the debugger l can see it. Thanks in advance.

char *foo (const char *_s) {
   char *str = new char[40];
   strcpy(str, _s);
   strcat(str, " *** ");
   strcat(str, _s);
   return str;
}

int main(int argc, char* argv[]) {
   char *c_string;

   c_string = foo("monster");
   printf("%s\n", c_string);
   delete []c_string; // is this correct before calling foo() again?

   c_string = foo("paragraph another");
   printf("%s\n", c_string);
   delete []c_string;

   getch();
   return 0;
}

[laserlight]

Yes, you should do so otherwise you technically have a memory leak (although this is a short running program so it doesn't matter).

[vincentThorpe]

thats what l was thinking thank you. Yes this a small part of a program.

[flp1969]

Another tip, using only ISO functions from string.h:

char *foo( char *s )
{
  char *p;
  char tmp;
  ssize_t size;

  // get the size of final string.
  size = snprintf( &tmp, 1, "%s *** %s", s, s );

  // allocate space, fill the buffer and return the pointer.
  p = new char[size+1];
  sprintf( p, "%s *** %s", s, s );
  return p;
}