CODEWITHSUNDEEP
java
alex23434
alex23434

Reputation: 399

How can I check for duplicate values without making an array?

I have a program that deals 20 cards based on the value of random numbers. So far it works to deal cards such as King of Spades, 2 of Hearts, etc. My job is to check whether or not the cards are duplicate using a method, but without an array. Here is my solution to checking duplicates which doesn't work for obvious reasons: 

    public class Driver {
        public static void main(String [] args) {

            for (int i = 0; i < 20; i++){
                Cards card1 = new Cards();
                Cards card2 = card1;
                if (card1 == card2) {
                    card1 = new Cards(); 
                }
                System.out.println(card1);
            }
        }
    }

Here is my support class: 

import java.util.Random;

public class Cards {

    String hearts = "Hearts";
    String diamonds = "Diamonds";
    String clubs = "Clubs";
    String spades = "Spades";

    String suit; 
    int cardNumber; 
    String numberName; 
    String suitName;
    Random randomNum = new Random();

    public Cards () {

    }

    public String suit() {
        int theRandom = randomNum.nextInt(4);

        if (theRandom == 0 ) {           
            suitName = "hearts";
        }
        else if ( theRandom == 1) {
            suitName = "diamonds"; 
        }
        else if (theRandom == 2) {
            suitName = "clubs";
        }
        else {
            suitName = "spades";
        }
        return suitName;
    }
    public String number() {
        int theRandomNum = randomNum.nextInt(12 + 1); 

        if ( theRandomNum == 1 ) {

            numberName = "Ace";
        }
        else if ( theRandomNum == 2) {
            numberName = "2";
        }
        else if ( theRandomNum == 3) {
            numberName = "3";
        }
        else if ( theRandomNum == 4) {
            numberName = "4";
        }
        else if ( theRandomNum == 5) {
            numberName = "5";
        }
        else if ( theRandomNum == 6) {
            numberName = "6";
        }
        else if ( theRandomNum == 7) {
            numberName = "7";
        }
        else if ( theRandomNum == 8) {
            numberName = "8";
        }
        else if ( theRandomNum == 9) {
            numberName = "9";
        }
        else if ( theRandomNum == 10) {
            numberName = "10";
        }
        else if ( theRandomNum == 11) {
            numberName = "Jack";
        }
        else if ( theRandomNum == 12) {
            numberName = "Queen";
        }
        else if ( theRandomNum == 13) {
            numberName = "King";
        } 
        return numberName;
    }

    public String toString()
    {
        if (number() == "null") {
            return ("3" + " of " + suit());
        }

        return (number() + " of " + suit());
    }
}

Upvotes: 1

Views: 502

Answers (2)

Aron_dc
Aron_dc

Reputation: 863

First your code has a small mistake

int theRandomNum = randomNum.nextInt(12 + 1)

while, determining from your following code you actually mean

int theRandomNum = randomNum.nextInt(12)+1

To store what cards you already had, you can just introduce a String and fill it step by step, always testing if the card you want to accept is not already contained in this String.

//This goes above the loop where you create your cards
String cards = "";

//This goes into the loop
while(cards.contains(card1.toString()){
    card1 = new Cards();
}
cards += card1.toString() + "#"; //Using # as a delimiter
System.out.println(card1);


//At the end you could also print your set of cards
System.out.println(cards);

It's not a very nice approach because you're not permitted to use arrays or similar structures but should do its work.

Please also keep in mind that class names are supposed to be singular. So not Cards but Card.

Upvotes: 1

phflack
phflack

Reputation: 2727

For using a large String to store the cards that have been chosen:

String cards = "";

for(int i = 0; i < 20; i++)
{
    Cards card = new Cards();
    while(cards.contains(card.toString()))
        card = new Cards(); //keep generating a random card until it's a new card
    cards += card.toString(); //add the card to the string of cards
    System.out.println(card);
}

This code would go inside the main method of your Driver class

Upvotes: 1

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