Task: Rosetta Code_Rank languages by popularity
C: #include <stdio.h>
#include <stdlib.h>
#include <string.h>

const char * lang_url = "http:
		"list=categorymembers&cmtitle=Category:Programming_Languages&"
		"cmlimit=500&format=json";
const char * cat_url = "http:

#define BLOCK 1024
char *get_page(const char *url)
{
	char cmd[1024];
	char *ptr, *buf;
	int bytes_read = 1, len = 0;
	sprintf(cmd, "wget -q \"%s\" -O -", url);
	FILE *fp = popen(cmd, "r");
	if (!fp) return 0;
	for (ptr = buf = 0; bytes_read > 0; ) {
		buf = realloc(buf, 1 + (len += BLOCK));
		if (!ptr) ptr = buf;
		bytes_read = fread(ptr, 1, BLOCK, fp);
		if (bytes_read <= 0) break;
		ptr += bytes_read;
	}
	*++ptr = '\0';
	return buf;
}

char ** get_langs(char *buf, int *l)
{
	char **arr = 0;
	for (*l = 0; (buf = strstr(buf, "Category:")) && (buf += 9); ++*l)
		for (	(*l)[arr = realloc(arr, sizeof(char*)*(1 + *l))] = buf;
			*buf != '"' || (*buf++ = 0);
			buf++);

	return arr;
}

typedef struct { const char *name; int count; } cnt_t;
cnt_t * get_cats(char *buf, char ** langs, int len, int *ret_len)
{
	char str[1024], *found;
	cnt_t *list = 0;
	int i, llen = 0;
	for (i = 0; i < len; i++) {
		sprintf(str, "/wiki/Category:%s", langs[i]);
		if (!(found = strstr(buf, str))) continue;
		buf = found + strlen(str);

		if (!(found = strstr(buf, "</a> ("))) continue;
		list = realloc(list, sizeof(cnt_t) * ++llen);
		list[llen - 1].name = langs[i];
		list[llen - 1].count = strtol(found + 6, 0, 10);
	}
	*ret_len = llen;
	return list;
}

int _scmp(const void *a, const void *b)
{
	int x = ((const cnt_t*)a)->count, y = ((const cnt_t*)b)->count;
	return x < y ? -1 : x > y;
}

int main()
{
	int len, clen;
	char ** langs = get_langs(get_page(lang_url), &len);
	cnt_t *cats = get_cats(get_page(cat_url), langs, len, &clen);
	qsort(cats, clen, sizeof(cnt_t), _scmp);
	while (--clen >= 0)
		printf("%4d %s\n", cats[clen].count, cats[clen].name);

	return 0;
}

C++: #include <string>
#include <boost/regex.hpp>
#include <boost/asio.hpp>
#include <vector>
#include <utility>
#include <iostream>
#include <sstream>
#include <cstdlib>
#include <algorithm>
#include <iomanip>

struct Sort { 
   bool operator( ) ( const std::pair<std::string,int> & a , const std::pair<std::string,int> & b ) 
      const {
	 return a.second > b.second ;
      }
} ;

int main( ) {
   try {
      
      boost::asio::io_service io_service ; 
      boost::asio::ip::tcp::resolver resolver ( io_service ) ;
      boost::asio::ip::tcp::resolver::query query ( "rosettacode.org" , "http" ) ;
      boost::asio::ip::tcp::resolver::iterator endpoint_iterator = resolver.resolve( query ) ;
      boost::asio::ip::tcp::resolver::iterator end ;
      boost::asio::ip::tcp::socket socket( io_service ) ;
      boost::system::error_code error = boost::asio::error::host_not_found ;
      
      while ( error && endpoint_iterator != end ) {
	 socket.close( ) ;
	 socket.connect( *endpoint_iterator++ , error ) ;
      }
      if ( error ) 
	 throw boost::system::system_error ( error ) ;
      
      boost::asio::streambuf request ;
      std::ostream request_stream( &request ) ;
      request_stream << "GET " << "/mw/index.php?title=Special:Categories&limit=5000" << " HTTP/1.0\r\n" ;
      request_stream << "Host: " << "rosettacode.org" << "\r\n" ;
      request_stream << "Accept: */*\r\n" ;
      request_stream << "Connection: close\r\n\r\n" ;
      
      boost::asio::write( socket , request ) ;
      
      boost::asio::streambuf response ;
      std::istream response_stream ( &response ) ;
      boost::asio::read_until( socket , response , "\r\n\r\n" ) ;
      boost::regex e( "<li><a href=\"[^<>]+?\">([a-zA-Z\\+#1-9]+?)</a>\\s?\\((\\d+) members\\)</li>" ) ;
      
      std::ostringstream line ;
      std::vector<std::pair<std::string , int> > languages ; 
      boost::smatch matches ;
      while ( boost::asio::read( socket , response , boost::asio::transfer_at_least( 1 ) , error ) ) {
	 line << &response ;
	 if ( boost::regex_search( line.str( ) , matches , e ) ) {
	    std::string lang( matches[2].first , matches[2].second ) ;
	    int zahl = atoi ( lang.c_str( ) ) ;
	    languages.push_back( std::make_pair( matches[ 1 ] , zahl ) ) ;
	 }
	 line.str( "") ;
      }
      if ( error != boost::asio::error::eof ) 
	 throw boost::system::system_error( error ) ;
      
      std::sort( languages.begin( ) , languages.end( ) , Sort( ) ) ;
      int n = 1 ;
      for ( std::vector<std::pair<std::string , int> >::const_iterator spi = languages.begin( ) ;
	    spi != languages.end( ) ; ++spi ) {
	 std::cout << std::setw( 3 ) << std::right << n << '.' << std::setw( 4 ) << std::right <<  
	 spi->second   << " - " << spi->first << '\n' ;
	 n++ ;
      }
   } catch ( std::exception &ex ) {
      std::cout << "Exception: " << ex.what( ) << '\n' ;
   }
   return 0 ;
}