Pointer Question

[Arcadiu]

Sorry, I'm back already. I've just been reading this book on Obj C which was recommended by a few people here on the forums and I have come across a problem in the following code

#import <Foundation/Foundation.h> 
int main (int argc, const char * argv[]) 
{ 
  const char *words[4]  // What purpose does that pointer bring? Why do i need it?
    = {  "Joe- Bob \"Handyman\" Brown", 
      "Jacksonville \"Sly\" Murphy", 
      "Shinara Bain", 
      "George \"Guitar\" Books" }; 
  int wordCount = 4; 
  int i; 
  for (i = 0; i < wordCount; i++) { 
    NSLog (@"%s is %d characters long", 
        words[i], strlen(words[i])); 
  } 
  return (0); 
} // main

I just am wondering why i need a little asterisk, and what am i pointing the array of words to? This is my real taste of OOP ever and the book I'm reading hasn't made any comment about that asterisk when it walks through the code?

Thanks for your time

Arc

[smasher]

Let me try two ways -

(1) The "just because" - strlen expects you to pass a pointer, not the actual data, so you must pass a pointer.
strlen() - Standard C String & Character - C Programming Reference - eLook.org

(2) Pointers are addresses. When dealing with strings (and later with objects) it's easier to pass the address of the object, which is only four bytes, instead of copying the whole string or object.

This also has another advantage; if you have the address of the original string or object, you can make changes to that string or call methods on that object and they'll be reflected in the original. If you passed strings or object by value, the way that ints and floats usually are, then you would not be able to affect the original.

The function strlen() doesn't change the contents of the string you pass, but some other functions do; it's an important use of pointers. Check out this answer for more details:

parameter passing: pass by value and pass by refernce

If you understand that, you probably understand pointers.

[Arcadiu]

wow thankyou very much you have been very helpful so far on this forum I am sure to remember your name comrade smasher