Printing for value of ArrayList Integer

Question

I'm working on a small game that essentially has piles of coins, and you must take some coins from a pile then the program prints out the resulting piles in the format:

Pile 1: ****
Pile 2: *****
Pile 3: **

I have an array list that store all these values like so:

List<Integer> coins = new ArrayList<>();
[4,5,2]

But I can't figure out how to get it to properly print the *'s.

How can I write this code to print out a * for each value in an element. IE 4 *'s if the element value is 4?

Here is my current method:

static void printGameState(){
    for(int i = 0; i <= coins.size()-1; i++){
        int k = i+1;
        System.out.print("Pile " + k + ": ");
        for(int j = 0; j <= coins.indexOf(i); j++){
            System.out.print("*");
        }
    }
}

user1134181 · Accepted Answer · 2016-02-13 18:37:34Z

1

Instead of using this condition:

j <= coins.indexOf(i);

Use this condition:

j < coins.get(i);

Try it:

for(int i = 0; i <= coins.size()-1; i++) {
    int k = i+1;

    System.out.print("Pile " + k + ": ");
    for(int j = 0; j < coins.get(i); j++) {
        System.out.print("*");
    }

    System.out.println();
}

You'll get:

Pile 1: ****
Pile 2: *****
Pile 3: **

answered Feb 13, 2016 at 18:37

user1134181

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1 Comment

Alkarin Over a year ago

Thank you this was very helpful. If I wanted to subtract the value of one of the arraylist elements, how would I go about doing this? coins.set(index, coins.get(index) - numCoins); would this be correct?

Calvin P. · Accepted Answer · 2016-02-13 18:45:21Z

1

You should be using < instead of <=. Also, you should be able to use get(i) to take the value at index i.

static void printGameState(){
    for(int i = 0; i < coins.size(); i++){
        int k = i+1;
        System.out.print("Pile " + k + ": ");
        for(int j = 0; j < coins.get(i); j++){
            System.out.print("*");
        }
    }
}

You could also make it a bit cleaner by forming another method to print * such as:

public void ast(int n){
    for(int i=0; i<n; i++){
        System.out.print("*");
    }
}

Then the contents of printGameState loop would be

int k = i+1;
System.out.print("Pile " + k + ": ");
ast(coins.get(i));

edited Feb 13, 2016 at 18:45

answered Feb 13, 2016 at 18:38

Calvin P.

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Comments

TimoStaudinger · Accepted Answer · 2016-02-13 18:54:55Z

1

You have to look at the values of the different stacks by accessing the array coins[i] instead of using the number of stacks as stack height:

static void printGameState(){
    for(int i = 0; i < coins.size(); i++) {
        // Build the coin stack
        String coinStack = "";
        for(int j = 0; j < coins.get(i); j++) {
            coinStack += "*";
        }

        // And output it
        System.out.println("Pile " + (i + 1) + ": " + coinStack);            
    }
}

edited Feb 13, 2016 at 18:54

answered Feb 13, 2016 at 18:32

TimoStaudinger

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1 Comment

Calvin P. Over a year ago

coins is not type int[] so coins[i] wouldn't work

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