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Saturday, 11 March 2017

Chapter 33 Exercise 10, Introduction to Java Programming, Tenth Edition Y. Daniel LiangY.

33.10 (Random cards) Write a JSF that displays four random cards from a deck of 52 cards, as shown in Figure 33.33. When the user clicks the Refresh button, four new random cards are displayed.


import javax.faces.bean.ManagedBean;
import javax.faces.bean.RequestScoped;

@ManagedBean
@RequestScoped
public class Exercise10 {
    private int[] deck = new int[54];
    
    public Exercise10() {
        changeCards();
    }
    
    public void changeCards() {
        for (int i = 0; i < deck.length; i++) {
            deck[i] = i + 1;
        }

        for (int i = 0; i < deck.length; i++) {
            int index = (int) (Math.random() * deck.length);
            int temp = deck[i];
            deck[i] = deck[index];
            deck[index] = temp;
        }
    }
    
    public int getCard0() {
        return deck[0];
    }  
    
    public int getCard1() {
        return deck[1];
    }

    public int getCard2() {
        return deck[2];
    }
    
    public int getCard3() {
        return deck[3];
    }
    
}

<?xml version='1.0' encoding='UTF-8' ?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml"
      xmlns:h="http://xmlns.jcp.org/jsf/html">
    <h:head>
        <title>Exercise10</title>
    </h:head>
    <h:body><h:form><center><br /><br />
        Display Four Random Cards<br />
        <br />
        <table><tr>
        <td width="100"><center><h:graphicImage name="#{exercise10.card0}.png" library="cards"/></center></td>
        <td width="100"><center><h:graphicImage name="#{exercise10.card1}.png" library="cards"/></center></td> 
        <td width="100"><center><h:graphicImage name="#{exercise10.card2}.png" library="cards"/></center></td> 
        <td width="100"><center><h:graphicImage name="#{exercise10.card3}.png" library="cards"/></center></td> 
        </tr></table>
        <br />
        <h:commandButton value="Refresh" action="#{exercise10.changeCards()}"/>
    </center></h:form></h:body>
</html>

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