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indefinite postponement

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snowedin

Technical User
Mar 18, 2004
2
US
What is it? I need to modify a card shuffling program to make it more efficient that uses indefinite postponement. I need to make the program to avoid indefinite postponement! I am not sure of what to take out?

#include <iostream>

using std::cout;
using std::left;
using std::right;

#include <iomanip>

using std::setw;

#include <cstdlib> // prototypes for rand and srand
#include <ctime> // prototype for time

// prototypes
void shuffle( int [][ 13 ] );
void deal( const int [][ 13 ], const char *[], const char *[] );

int main()
{
// initialize suit array
const char *suit[ 4 ] =
{ "Hearts", "Diamonds", "Clubs", "Spades" };

// initialize face array
const char *face[ 13 ] =
{ "Ace", "Deuce", "Three", "Four",
"Five", "Six", "Seven", "Eight",
"Nine", "Ten", "Jack", "Queen", "King" };

// initialize deck array
int deck[ 4 ][ 13 ] = { 0 };

srand( time( 0 ) ); // seed random number generator

shuffle( deck );
deal( deck, face, suit );

return 0; // indicates successful termination

} // end main

// shuffle cards in deck
void shuffle( int wDeck[][ 13 ] )
{
int row;
int column;

// for each of the 52 cards, choose slot of deck randomly
for ( int card = 1; card <= 52; card++ ) {

// choose new random location until unoccupied slot found
do {
row = rand() % 4;
column = rand() % 13;
} while( wDeck[ row ][ column ] != 0 ); // end do/while

// place card number in chosen slot of deck
wDeck[ row ][ column ] = card;

} // end for

} // end function shuffle

// deal cards in deck
void deal( const int wDeck[][ 13 ], const char *wFace[],
const char *wSuit[] )
{
// for each of the 52 cards
for ( int card = 1; card <= 52; card++ )

// loop through rows of wDeck
for ( int row = 0; row <= 3; row++ )

// loop through columns of wDeck for current row
for ( int column = 0; column <= 12; column++ )

// if slot contains current card, display card
if ( wDeck[ row ][ column ] == card ) {
cout << setw( 5 ) << right << wFace[ column ]
<< " of " << setw( 8 ) << left
<< wSuit[ row ]
<< ( card % 2 == 0 ? '\n' : '\t' );

} // end if

} // end function deal
 
Modify do-while loop: place the next card on the next free slot after random selected one (by modulo 52). You may also randomize the initial deal with some kind of a shuffling simulation (see Knuth's book). For example, get 2 random positions (0..51: treat the matrix as 1D array) and swap cards. Repeat this swapping N times.
It's a finit alg with rather good distribution parameters.

 
Tell me more about Knuth's book?

Where could I get it?
 
Knuth's book is actually several volumes, very big, very deep, and definitely worth a look. But I'd try the local library first. If you're lucky they'll have it. I think it's called the art of computer programming or something. Very hot on theory of algorithms, and particularly good on "real-world" examples that make it easy to understand the problem. E.g. memory allocation done by considering best way for restaurant-staff to seat customers in order to maximise efficient use of restaurant!
 
snowedin, nice to see u have a copy of deitel + deitel c++ how to program! Snap!
 
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