Update euchre.cpp

smooth out wrinkles in argument-checking. all pass now, but then get 

#include <cstdio>
#include <cstring>
#include <cstdlib>
#include <assert.h>
#include "Game.h"


int main(int argc, char* argv[]) {
   //
   // READ ARGUMENTS:
   //
   cout << "HI!" << argc << endl;
   if(argc != 8) {
      exit(EXIT_FAILURE);
   }
   cout << "HI!" << argv[0] << endl;
   if(strcmp(argv[0], "./euchre") != 0) {
      exit(EXIT_FAILURE);
   }
   
   cout << "HI!" << endl;
   char* pack_filename = argv[1];
   // we don't ensure well-formed filename; that's handled at open-time. 

   cout << "HI!" << endl;
   bool shuffle; 
   if(strcmp(argv[2], "shuffle")==0) {
      shuffle = true;
   } else if(strcmp(argv[2], "no shuffle")==0) {
      shuffle = false;
   } else {
      exit(EXIT_FAILURE);
   }

   cout << "HI!" << endl;
   int points_to_win = atoi(argv[3]);  // TODO: separately ensure well-formed integer!
   if(!(1<=points_to_win && points_to_win<=100)) {
      exit(EXIT_FAILURE);
   }

   cout << "HI!" << endl;
   char* player_names[NUM_PLAYERS];
   for(int i = 0; i < NUM_PLAYERS; i++) {
      player_names[i] = argv[4+i];
   }

   //
   // PLAY EUCHRE!
   //
   Game game;
   Game_init(&game, pack_filename, shuffle, points_to_win, player_names);
   Game_play(&game);
   
   return 0;
}