Hi there, I have a really quick question about a shuffling and dealing cards program I found in a book.
here's main:
// Fig. 8.27: fig08_27.cpp
// Card shuffling and dealing program.
#include "DeckOfCards.h" // DeckOfCards class definition
int main()
{
DeckOfCards deckOfCards; // create DeckOfCards object
deckOfCards.shuffle(); // shuffle the cards in the deck
deckOfCards.deal(); // deal the cards in the deck
return 0; // indicates successful termination
} // end mainMember functions:
// Fig. 8.26: DeckOfCards.cpp
// Member-function definitions for class DeckOfCards that simulates
// the shuffling and dealing of a deck of playing cards.
#include <iostream>
using std::cout;
using std::left;
using std::right;
#include <iomanip>
using std::setw;
#include <cstdlib> // prototypes for rand and srand
using std::rand;
using std::srand;
#include <ctime> // prototype for time
using std::time;
#include "DeckOfCards.h" // DeckOfCards class definition
// DeckOfCards default constructor initializes deck
DeckOfCards::DeckOfCards()
{
// loop through rows of deck
for ( int row = 0; row <= 3; row++ )
{
// loop through columns of deck for current row
for ( int column = 0; column <= 12; column++ )
{
deck[ row ][ column ] = 0; // initialize slot of deck to 0
} // end inner for
} // end outer for
srand( time( 0 ) ); // seed random number generator
} // end DeckOfCards default constructor
// shuffle cards in deck
void DeckOfCards::shuffle()
{
int row; // represents suit value of card
int column; // represents face value of card
// for each of the 52 cards, choose a slot of the deck randomly
for ( int card = 1; card <= 52; card++ )
{
do // choose a new random location until unoccupied slot is found
{
row = rand() % 4; // randomly select the row (0 to 3)
column = rand() % 13; // randomly select the column (0 to 12)
} while( deck[ row ][ column ] != 0 ); // end do...while
// place card number in chosen slot of deck
deck[ row ][ column ] = card;
} // end for
} // end function shuffle
// deal cards in deck
void DeckOfCards::deal()
{
// initialize suit array
static const char *suit[ 4 ] =
{ "Hearts", "Diamonds", "Clubs", "Spades" };
// initialize face array
static const char *face[ 13 ] =
{ "Ace", "Deuce", "Three", "Four", "Five", "Six", "Seven",
"Eight", "Nine", "Ten", "Jack", "Queen", "King" };
// for each of the 52 cards
for ( int card = 1; card <= 52; card++ )
{
// loop through rows of deck
for ( int row = 0; row <= 3; row++ )
{
// loop through columns of deck for current row
for ( int column = 0; column <= 12; column++ )
{
// if slot contains current card, display card
if ( deck[ row ][ column ] == card )
{
cout << setw( 5 ) << right << face[ column ]
<< " of " << setw( 8 ) << left << suit[ row ]
<< ( card % 2 == 0 ? '\n' : '\t' );
} // end if
} // end innermost for
} // end inner for
} // end outer for
} // end function dealand header file:
// Fig. 8.25: DeckOfCards.h
// Definition of class DeckOfCards that
// represents a deck of playing cards.
// DeckOfCards class definition
class DeckOfCards
{
public:
DeckOfCards(); // constructor initializes deck
void shuffle(); // shuffles cards in deck
void deal(); // deals cards in deck
private:
int deck[ 4 ][ 13 ]; // represents deck of cards
}; // end class DeckOfCardsOk, so I don't quite understand how the
srand()function is used, (line 34 of main) in combination with the functions
rand()line 48 and 49. Why do we need srand() in this program, isn't rand() enough?
thanks
