String assignment from method

[Hai-Tan Le]

Hey all, I get a return int value from my method. How do I set the value to a string character? My string character would change depending on the random int value generated.
I think I should be using an array, but I had problem setting a int to a String. please help, thanks

import acm.program.*;
import acm.util.*;

	public void run(){
		println("This program displays a randomly chosen card.");
		int card1=randomCard();
		int card2=randomCard2();
		println(card1+" of "+card2);
	}
	
	private int randomCard() {
		int c1 = rgen.nextInt(1, 13);		
		
		return c1;
	}
	
	private int randomCard2() {
		int c2 = rgen.nextInt(1, 4);
		return c2;
	}
	
	private RandomGenerator rgen = new RandomGenerator();
	
}

[fred rosenberger]

there are a couple of things you'd need to do...

First, you'd need to declare your method to return a string instead of an int:

private String randomCard() { 
//etc

Then, you'd need to build a string in your method and return that. So, after you get your random number, you probably would convert it (depending on the value) to "one", "two"... or "diamond", "heart", etc. and return that string instead of your int.

[Campbell Ritchie]

I find it a bit difficult to understand the question. Do you mean, "how do you get ace instead of 1?" That would require a String[] array, or a Map<Integer, String>. The array would look something like

String[] suits = {"Clubs", "Diamonds", "Hearts", "Spades"};

and the Map might be filled like this . . .
myMap.put(1, "Clubs");
myMap.put(2, "Diamonds"); etc etc.

[fred rosenberger]

Campbell, you are slipping. I beat you by over a minute this time!

[Unnar Björnsson]

How do I set the value to a string character?

I'm probably misunderstanding the question but I'll still answer it anyway. You turn int into String by concatenating it with a String, it can be an empty String like:

""+randomCard()

You can do the reverse with Integer.parseInt() like so:

Integer.parseInt("1990")

[fred rosenberger]

Unnar Björnsson wrote:I'm probably misunderstanding the question but I'll still answer it anyway. You turn int into String by concatenating it with a String, it can be an empty String like:

""+randomCard()

You can do the reverse with Integer.parseInt() like so:

Integer.parseInt("1990")

My guess is that is not what they want.

in the run() method on line 8, it looks like they are trying to print "Jack of Diamonds". Simply concatenating their int to "" would ultimately end up printing something like "8 of 2".

[Campbell Ritchie]

fred rosenberger wrote:Campbell, you are slipping. I beat you by over a minute this time!

Yes, I know, but I only bother when it's Rob

[Hai-Tan Le]

Here is my program. When I run it, the output is only "This program displays a randomly chosen card."

Am I missing something? Why isn't the card and suits printed?
Thanks again

import acm.program.*;
import acm.util.*;

public class add10Integers extends Program{
	/**
	 * 
	 */
	private static final long serialVersionUID = 1L;

	public void run(){
		println("This program displays a randomly chosen card.");
		String card=randomCard();
		String suits=randomCard2();
		println(card+" of "+suits);
	}
	
	private String randomCard() {
		int c1 = rgen.nextInt(2, 14);
		String[] card = new String[13];
		card[2]="2";
		card[3]="3";
		card[4]="4";
		card[5]="5";
		card[6]="6";
		card[7]="7";
		card[8]="8";
		card[9]="9";
		card[10]="10";
		card[11]="Jack";
		card[12]="Queen";
		card[13]="King";
		card[14]="Ace";
		return card[c1];
		
		
		
	}
	
	private String randomCard2() {
		int c2 = rgen.nextInt(1, 4);
		String[] suits = new String[4];
		suits[1] ="Spades";
		suits[2] ="Clovers";
		suits[3] ="Diamonds";
		suits[4] ="Hearts";
		return suits[c2];
	}
	
	private RandomGenerator rgen = new RandomGenerator();
	
}

[Christopher Nortje]

Hi Hai,

When you create a primitive array and specify the length, you are basically saying this array has X amount of values.
Example:

String[] card = new String[13];

you are expressing the the array named card has 13 values.

The first value of an array is always at index 0
Example:

card[0]="Value 1";

The last value of an array is always at index (length - 1)
Example:

card[12]="last Value";

In your case you need to increase your card size to 15, since your adding to the 14th index.
Example:

String[] card = new String[15];

The same goes for your suits, even though your only adding four values to that array, your starting at the second index suits[1] and ending at an unallocated index of suits[4], you would have to increase your suit size to 5.

your application is most likely throwing an java.lang.ArrayIndexOutOfBoundsException
See http://download.oracle.com/javase/1.4.2/docs/api/java/lang/ArrayIndexOutOfBoundsException.html

Have a look at this tutorial java arrays, this explains it in more detail.
http://download.oracle.com/javase/tutorial/java/nutsandbolts/arrays.html

Also note each time the method is executed that array is created.
If your using java 1.5 or greater you could read up on java enumeration.
http://download.oracle.com/javase/tutorial/java/javaOO/enum.html