//force NSLog disable
//uncomment to force NSLog disabling no matter what
//#define FORCE_NSLOG_DISABLE
//note: you will need to add the DEBUG symbol to your
//  project's preprocessor flags setting
#if !defined(DEBUG) || defined(FORCE_NSLOG_DISABLE)
//variadic MACROS may be gcc only
#	define NSLog(...) ;
#endif

This will replace all NSLog calls to no-ops, which is of course much cheaper than printing to stdout.

There’s a few ways you can go about using regular expressions in your C / C++ code.

1. The POSIX C regex library.  This presumes of course you are running on a Unix-ish system, e.g. Linux, Mac OSX, iPhone, BSD, etc.

   #include <regex.h>
   regex_t re;
   const char* re_string = "m[Aa]t?ch.*";
   if(regcomp(&re, re_string, REG_NOSUB) != 0){
     std::cerr << "Invalid regular expression" << std::endl;
     return;
   }
   if(regexec(&re, "mAchzzzzaaaa!!!!oneone", (size_t)0, NULL, 0) == 0)
     std::cout << "Found a match!" << std::endl;
   

2. The Boost Regex POSIX-like API.  This is a C wrapper to the Boost Regex library, which allows you to use the library with POSIX regex calls.

   #include <boost/regex.h>
   // otherwise use just as you would the POSIX lib

3. The Boost Regex C++ API, straight no chaser.

   #include <boost/regex.hpp>
   boost::regex re("m[Aa]t?ch.*");
   if(boost::regex_match("mAchzzzzaaaa!!!!oneone", re))
     std::cout << "Found a match!" << std::end;

This is but a taste of what’s available.  Peep the POSIX regex API and the Boost Regex Documentation.  Note, Boost Regex is one of only a handful of the Boost packages that needs to be explicitly built and linked with your code.

I needed a way to test the existence of a file. Version 1 called fopen and tested for NULL, but this also meant some nasty ifs and fclose logic.

Here’s the better way:

#include <iostream>
#include <cerrno>
#include <sys/stat.h>
struct stat fileInfo;
const char* filename = "myFile";
if(stat(filename, &fileInfo) != 0){ //error
  if(errno == ENOENT){
    std::cerr << "File " << myFile << " doesn't exist" << std::endl;
  else{ //any other error
    std::cerr << "Error getting info on file " << filename << ": "
              << strerror(errno) << std::endl;
  }
}

File existence is but one of the few things you check for.  Just be careful what you check for though, as many of the attributes in struct stat are Unix only.

See stat()’s documentation for more details.

#include <boost/shared_ptr.hpp>
using boost::shared_ptr;
#include <vector>
class A{...};
typedef shared_ptr<A> A_ptr;
...
vector<A_ptr> vec_of_a;
for(int i = 0; i < 10; i++){
  A_ptr p(new A());
  vec_of_a.push_back(p);
}
...
// do stuff with vector
...
vec_of_a.clear(); //automagically calls delete on all A_ptrs in vector

To avoid having to call vector::clear(), you can make the vector itself a boost::shared_ptr or boost::scoped_ptr; this will cause the vector itself to be automatically reclaimed, along with its contents.

See Boost’s Smart Pointer Documentation for more info.