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why doesnt my random number generator method work? just keeps putting out same #?

Posted on 2004-08-15
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Last Modified: 2010-03-31
     import java.io.*;
import java.util.*;

//***************************************************************
// Program that simulates the game of Black Jack between one player and
// a simulated dealer.  
//***************************************************************
class Blackjack

{
      public static void main(String args[])throws IOException
      {
      BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
      
      final int blackjack=21;
      int pcard1=0, pcard2=0, pcard3=0, pcard4=0, pcard5=0, dcard1=0, dcard2=0, dcard3=0, dcard4=0, dcard5=0;
      int dealer=0, player=0, count=0;
      char face, another;

//*************************************************************************
//21Dealing first hand
//*************************************************************************      
      
      System.out.println("Player      Dealer");
      for (count=0; count<2; ++count)
      {  pcard1=deal();
         System.out.print(" \t"+pcard1);
      }
      for (count=0; count<2; ++count)
      {  dcard1=deal();
         System.out.print("\t"+dcard1);
      }            

       static int deal()
      {
      Random generator = new Random();
      int card;

      card = generator.nextInt(13) + 1;

      return card;
      } // method deal
0
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Question by:hedge243
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10 Comments
 
LVL 86

Expert Comment

by:CEHJ
ID: 11805974
Create your Random once in the constructor of Blackjack
0
 

Author Comment

by:hedge243
ID: 11806006
can you show me what you mean, I am very new at this.
0
 
LVL 92

Expert Comment

by:objects
ID: 11806008
static int deal()
{
     int card = (int) Math.random()*13 + 1;

     return card;
} // method deal
0
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LVL 92

Expert Comment

by:objects
ID: 11806015
missed some brackets, that should be:

static int deal()
{
     int card = (int) (Math.random()*13) + 1;

     return card;
} // method deal

0
 
LVL 86

Accepted Solution

by:
CEHJ earned 100 total points
ID: 11806038
>>can you show me what you mean, I am very new at this.

Yes, something like this. Java is an object-oriented language and you should try to produce object-oriented code, i.e. non-procedural:


import java.io.*;
import java.util.*;

//***************************************************************
// Program that simulates the game of Black Jack between one player and
// a simulated dealer.
//***************************************************************
class Blackjack {
      private Random dealer;

      public Blackjack() {
            dealer = new Random();
      }

      public static void main(String args[]) throws IOException {
            BufferedReader in = new BufferedReader(new InputStreamReader(System.in));

            final int blackjack = 21;
            int pcard1 = 0;
            int pcard2 = 0;
            int pcard3 = 0;
            int pcard4 = 0;
            int pcard5 = 0;
            int dcard1 = 0;
            int dcard2 = 0;
            int dcard3 = 0;
            int dcard4 = 0;
            int dcard5 = 0;
            int dealer = 0;
            int player = 0;
            int count = 0;
            char face;
            char another;

//*************************************************************************
//21Dealing first hand
//*************************************************************************
    Blackjack bj = new Blackjack();
            System.out.println("Player     Dealer");
            for (count = 0; count < 2; ++count) {
                  pcard1 = bj.deal();
                  System.out.print(" \t" + pcard1);
            }
            for (count = 0; count < 2; ++count) {
                  dcard1 = bj.deal();
                  System.out.print("\t" + dcard1);
            }
      }

      public int deal() {
            return dealer.nextInt(13) + 1;
      }
      // method deal
}
0
 
LVL 92

Expert Comment

by:objects
ID: 11806108
Simply replacing your deal method with the one i posted above will fix it.
Moving where u create Random will not make any difference, in fact you don't need to create one at all.

0
 

Author Comment

by:hedge243
ID: 11806768
so I need to make sure I know what Im doing, do my notes look right?

mport java.io.*;
import java.util.*;

//***************************************************************
// Program that simulates the game of Black Jack between one player and
// a simulated dealer.
//***************************************************************
class Blackjack
{
     private Random dealer;

     

     public static void main(String args[]) throws IOException {
          BufferedReader in = new BufferedReader(new InputStreamReader(System.in));

          final int blackjack = 21;
          int pcard1 = 0;
          int pcard2 = 0;
          int pcard3 = 0;
          int pcard4 = 0;
          int pcard5 = 0;
          int dcard1 = 0;
          int dcard2 = 0;
          int dcard3 = 0;
          int dcard4 = 0;
          int dcard5 = 0;
          int dealer = 0;
          int player = 0;
          int count = 0;
          char face;
          char another;

//*************************************************************************
//21Dealing first hand
//*************************************************************************
    Blackjack bj = new Blackjack();
          System.out.println("Player     Dealer");
          for (count = 0; count < 2; ++count) {
               pcard1 = bj.deal();
               System.out.print(" \t" + pcard1);
          }
          for (count = 0; count < 2; ++count) {
               dcard1 = bj.deal();
               System.out.print("\t" + dcard1);
          }
     } // method main


//****************************************************************************
//method to choose random number or instantiate an object?
//****************************************************************************
      public Blackjack()
      {
          dealer = new Random();
      } // method Blackjack

//****************************************************************************
// method to return # from 1 to 13
//****************************************************************************
     public int deal()
     {
        return dealer.nextInt(13) + 1;
     }// method deal

     
} // class Blackjack
0
 
LVL 92

Expert Comment

by:objects
ID: 11806783
Simpler just to not worrying about Using Randon class at all, There is a static method Math.random() that does all you need. See the code I costed above for how to use it.
0
 
LVL 86

Expert Comment

by:CEHJ
ID: 11808024
>>//method to choose random number or instantiate an object?

should probably read

// Instantiate a Blackjack instance and create a Random as 'dealer' to deal random cards

Incidentally, shouldn't deal be producing 2 to 14? (I don't know the rules of blackjack)
0
 
LVL 3

Expert Comment

by:RuadRauFlessa
ID: 11825995
CEHJ,
Looking at his deal function it looks correct since "A" = 1 or 11 and everything above "10" from there on out = 10

It all actually depends on how you want to represent the whole thing

if you say 1 = 2, 2 = 3 .... 12 = "Q", 13 = "K", 14 = "A"

Then you would be correct.
0

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