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Re: What's the difference between a C++ and ObjC String?
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Re: What's the difference between a C++ and ObjC String?


  • Subject: Re: What's the difference between a C++ and ObjC String?
  • From: "Frederick C. Lee" <email@hidden>
  • Date: Sat, 2 Jul 2005 08:00:57 -0700

Thanks for the info.

I'm quite familiar with the 'front-end' of NSString and the C-string architecture.
I'm trying to 'glue' some C++ routines within Objective-C with the premise that there's a huge C++ world out there that I could to tap from within Objective-C (aka "Objective-C++") rather than re-write the entire logic.
And on a side note, I'll toy with meshing C++ containers (Vector/List templates) with Objective-C containers: to see if I can effectively glean data from the C++ side.


Ric.

On Jul 1, 2005, at 5:49 PM, Todd Blanchard wrote:

There are C "strings" which are just arrays of char terminated with zero. They look like:

"This is a string"
char* s = 0;
const char *t = "Hi there";
char a[] = "an array of char just big enough to hold this text plus a null terminator";
char b[256] = "an array of 256 with extras set to zeros";


C++ has resorted to a number of string classes - the most modern of which is the std::string class found in the STL. You can generally ignore this as it's cack and useless in the Cocoa environment.

Cocoa uses instances of NSString*.  Cocoa strings look like this:

NSString* @"An NSString literal"
NSString* fromCString = [NSString stringWithUTF8String: "A C string for initialization"];
NSString* fromNSString = [NSString stringWithString: @"Another NSString literal"];
NSString* formattedString = [NSString stringWithFormat: @"This is how you do sprintf type things %d %@\n",50,someObject];


etc.  You want to use NSString wherever possible in cocoa programming.

NSStrings are immutable - you cannot change them. If you want a modifyable string, create the subclass NSMutableString instead. This is in sharp contrast to std::string which is mutable vs const std::string which is not.

Welcome to the varsity.  Shout if you need more help.

On Jul 1, 2005, at 4:12 PM, Frederick C. Lee wrote:


I read that C strings are null terminated whereas C++ strings are not.
Which leads me to ask, is there any difference between C++ and ObjC strings?


Ric.

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References: 
 >What's the difference between a C++ and ObjC String? (From: "Frederick C. Lee" <email@hidden>)

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