ch1.cpp

这个针对Essential C++这本书的代码

/**************************************************
 * Essential C++ -- Stanley Lippman
 * Addison-Wesley 
 * ISBN 0-201-48518-4
 * homepage: www.objectwrite.com
 * email: [e-mail]
 *************************************************/

#include "ch1.h"

pvec Fibonacci_gen_elems( int pos ) 
{ 
	static vector<unsigned int> _elems;

	if ( ! check_integrity( pos ))
		 return 0;

    if ( _elems.empty() )
       { _elems.push_back( 1 ); _elems.push_back( 1 ); }

    if ( _elems.size() < pos )
	{
		    int ix = _elems.size();
			int n_2 = _elems[ ix-2 ], 
				n_1 = _elems[ ix-1 ];

			int elem;
			for ( ; ix < pos; ++ix ){
				    elem = n_2 + n_1; 
					_elems.push_back( elem );
					n_2 = n_1; n_1 = elem;
			}
	 }

	 return &_elems;
}  

   
pvec Pell_gen_elems( int pos )    
{ 
	static vector< unsigned int> _elems;

	if ( ! check_integrity( pos ))
		 return 0;

    if ( _elems.empty() )
       {  _elems.push_back( 1 ); _elems.push_back( 2 ); }

    if ( _elems.size() < pos )
	{
		    int ix = _elems.size();
			int n_2 = _elems[ ix-2 ], 
				n_1 = _elems[ ix-1 ];

			int elem;
			for ( ; ix < pos; ++ix ){
				    elem = n_2 + 2 * n_1; 
					_elems.push_back( elem );
					n_2 = n_1; n_1 = elem;
			}
	 }

	 return &_elems;
}
   
pvec Lucas_gen_elems( int pos ) 
{    
	static vector<unsigned int> _elems;

	if ( ! check_integrity( pos ))
		 return 0;

    if ( _elems.empty() )
       {  _elems.push_back( 1 ); _elems.push_back( 3 ); }

    if ( _elems.size() < pos )
	{
		    int ix = _elems.size();
			int n_2 = _elems[ ix-2 ], 
				n_1 = _elems[ ix-1 ];

			int elem;
			for ( ; ix < pos; ++ix ){
				    elem = n_2 +  n_1; 
					_elems.push_back( elem );
					n_2 = n_1; n_1 = elem;
			}
	 }

	 return &_elems;
}    
   
pvec Triangular_gen_elems( int pos ) 
{
	static vector<unsigned int> _elems;

	if ( ! check_integrity( pos ))
		 return 0;

    if ( _elems.size() < pos )
	{
		int ix = _elems.size() ? _elems.size()+1 : 1;
		for ( ; ix <= pos; ++ix )
			  _elems.push_back( ix*(ix+1)/2 );
	}

	return &_elems;
}

pvec Square_gen_elems( int pos ) 
{
	static vector<unsigned int> _elems;

	if ( ! check_integrity( pos ))
		 return 0;

    if ( _elems.size() < pos )
	{
		int ix = _elems.size() ? _elems.size()+1 : 1;
		for ( ; ix <= pos; ++ix )
			  _elems.push_back( ix*ix );
	}

	return &_elems;
}   
    
pvec Pentagonal_gen_elems( int pos ) 
{
	static vector<unsigned int> _elems;

	if ( ! check_integrity( pos ))
		 return 0;

    if ( _elems.size() < pos )
	{
		int ix = _elems.size() ? _elems.size()+1 : 1;
		for ( ; ix <= pos; ++ix )
			  _elems.push_back( ix*(3*ix-1)/2 );
	}

	return &_elems;
}

pfunc gen_elems[] = 
{ 0,
  Fibonacci_gen_elems,
  Pell_gen_elems,
  Lucas_gen_elems,
  Triangular_gen_elems,
  Square_gen_elems,
  Pentagonal_gen_elems
};

const char *name_seq[] = { "Invalid Sequence",
   "Fibonacci", "Pell", "Lucas",
   "Triangular", "Square", "Pentagonal"
};

int level_size[] = { 8, 8, 32, 128, 512 };

const char* wrong_msg[] = {
 "Oops! Nice guess but not quite it.",
 "Hmm. Sorry. Wrong again.",
 "Ah, this is harder than it looks, isn't it?",
 "It must be getting pretty frustrating by now!"
};

void display_statistics( user_profile *puser )
{
	cout << "Game Statistics for " << puser->name << "\n\t"
		 << "# guesses: " << puser->guesses << "\n\t"
		 << "# correct: " << puser->correct << "\n\t"
		 << "% correct: " 
		 << (static_cast<float>( puser->correct ) / static_cast<float>( puser->guesses )) * 100 << endl;
}

bool greet_user( user_profile *puser )
{
      cout << "Hi. What's your name? ";

	  string nm;
	  cin >> nm;

	  if ( nm.empty() || nm[ 0 ] == ' ' ){
		   cout << "ok. I guess you don't want to play. See ya!\n";
		   return false;
	  }

	  cout << "Hi, " << nm
		   << " Would you like to play Guess the Sequence? (y/n) ";

	  char ch;
	  cin >> ch;

	  if ( ch != 'y' && ch != 'Y' ){
		   cout << "ok. I'm sorry you don't want to play.\n";
		   return false;
	  }

	  cout << "\n\n" << "Hey, that's great, " << nm << ".\n"
		   << "We'll start in just a moment.\nIt\'s simple, really!\n"
		   << "I will print out two elements of a sequence\n"
		   << "You just answer with the element value that comes next!\n\n";

	  cout << "Oh, by the way, do you consider yourself a\n\t"
		   << "beginner     -- enter 1\n\t"
		   << "intermediate -- enter 2\n\t"
		   << "advanced     -- enter 3\n\t"
		   << "guru         -- enter 4\n\t" << endl;

	  int level;
	  cin >> level;

	  if ( level < 1 || level > 4) level = 4;

	  init_user( puser, nm, level );
	  return true;
}

void print_seq( user_profile *puser )
{
	for ( int i = 0; i < puser->cur_seq_vec->size(); ++i )
		  cout << (*puser->cur_seq_vec)[i] << ' ';
	cout << endl;
}

void display_seq( user_profile *puser )
{
	pvec p = seq_vec( puser ); 
	cout << "The first two elements of the series are: "
		 << (*p)[ puser->pos-3 ] << ", " << (*p)[ puser->pos-2 ] 
		 << "\nWhat is the next element? ";
}

void set_up_index( user_profile *puser )
{
	static string wherefrom( "set_up_index" );

	// randomly pick a position within the sequence
	puser->pos = rand() % ( level_size[ puser->level ] );

	// position represents 
	if ( puser->pos < 3 ) puser->pos += 3;
	
	set_seq_vec( puser, (*gen_elems[ puser->cur_seq ])( puser->pos ));
	trace( wherefrom, "new position: ", puser->pos );
}

void reset_seq( user_profile *puser )
{
	static string wherefrom( "reset_seq" );

	int new_seq = gen_seq_id( reinterpret_cast<unsigned int>( puser ));
	if ( new_seq == puser->cur_seq )
		 new_seq = new_seq < ns_cnt ? new_seq+1 : 1;

	puser->cur_seq = static_cast<num_sequence>( new_seq );

	set_up_index( puser );

	print_seq( puser );
	trace( wherefrom, "new sequence: ", name_seq[ puser->cur_seq ]);
}

void init_user( user_profile *puser, const string& nm, int level )
{
	static string wherefrom( "init_user" );

	puser->name = nm;
	puser->guesses = 0;
	puser->correct = 0;
	puser->level = level;

	reset_seq( puser );

    trace( wherefrom, nm, puser->cur_seq, level );
}	

bool correct_guess( user_profile *puser, int guess )
{
	pvec p = seq_vec( puser ); 
	if ( guess == (*p)[ puser->pos-1 ] )
		 return true;
	return false;
}

void play_game( user_profile *puser )
{
	bool next_seq  = true;      // show next sequence?
    bool go_for_it = true;      // user wants to guess?
    bool got_it    = false;     // user guessed correctly?
	int  num_tries;				// number of tries per sequence

    while ( next_seq == true )
	{
		num_tries = 0;
	    display_seq( puser );
        while (( got_it == false ) &&
               ( go_for_it == true ))
        {
             unsigned int usr_guess;
			 cin >> usr_guess;

              if ( correct_guess( puser, usr_guess ))
			  {
				  bump_correct( puser );
				  got_it = true;
				  cout << "Hey, most excellent! \n\t"
					   << usr_guess << " is element # "
					   << puser->pos << " of the " 
					   << name_seq[ puser->cur_seq ] << " sequence.\n";
			  }
			  else 
			  {
				  bump_guess( puser );
                  cout << wrong_msg[ num_tries < ns_wrong_msg ? num_tries : ns_wrong_msg-1 ]
					   << " Would you like to try again? (y/n) ";

                  char usr_rsp;
				  cin >> usr_rsp;
 
                  if ( usr_rsp == 'N' || usr_rsp == 'n' )
                       go_for_it = false;
				  else { ++num_tries; cout << "Your next guess? "; }
			  }
        } 

        cout << "Want to try another sequence? (y/n) ";
        char try_again;
        cin >> try_again;

        if ( try_again == 'N' || try_again == 'n' )
             next_seq = false;
		else { got_it = false; reset_seq( puser ); }
	}
}