LIBCURL + C + POST

#include <stdio.h>
#include <curl/curl.h>

int main( void )
{
   int a = 1, b, c;
   char post[1000];
   CURL *curl;
   CURLcode res;

   /* In windows, this will init the winsock stuff */
   curl_global_init( CURL_GLOBAL_ALL );

   /* get a curl handle */
   curl = curl_easy_init();
   if ( curl ) {
      // aqui é definido o formulario que recebera os dados da requisição (POST).
      curl_easy_setopt( curl, CURLOPT_URL, "http://127.0.0.1/triangulo.php" );

      while ( a > 0 ) {
         printf( "\nDigite os 3 lados do triangulo separados por espaco: " );
         scanf( "%d %d %d", &a, &b, &c );

         sprintf( post, "n1=%d&n2=%d&n3=%d", a, b, c ); //Aqui é definida as variaveis do POST

         curl_easy_setopt( curl, CURLOPT_POSTFIELDS, post );

         /* Perform the request, res will get the return code */
         res = curl_easy_perform( curl );

         if ( res != CURLE_OK ) // verifica se deu algum erro
            fprintf( stderr, "curl_easy_perform() failed: %s\n", curl_easy_strerror( res ) );

      }

      /* always cleanup */
      curl_easy_cleanup( curl );
   }
   curl_global_cleanup();
   return 0;
}