Align a String to the right using printf in Java

Question

I need to right justify the next output using Java:

class MyTree {

    public static void staircase(int n) {
        String myGraph = "#";
        for(int i=0; i<n; i++){
            for(int x = 0; x <=i; x++){
                if(x == i){
                    System.out.printf("%s\n", myGraph);
                }else{
                    System.out.printf("%s", myGraph);                    
                }
            }
        }
    }
}

I'm using printf function but I'm stuck, I tried different parameters but nothing seems to work; in case you have a suggestion please let me know.

Thanks

rzwitserloot · Accepted Answer · 2021-09-30 17:07:26Z

1

You can't right justify unless you know the 'length' of a line, and there's no way to know that. Not all things System.out can be connected to have such a concept.

If you know beforehand, you can use %80s for example. If you don't, what you want is impossible.

answered Sep 30, 2021 at 17:07

rzwitserloot

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2 Comments

htamayo Over a year ago

cool, thanks for the tip, one more question: in case the length of each line is determined by a variable, what would be a way to reference it, because something like System.out.printf(%myvars, data) didn't work, any hints?

rzwitserloot Over a year ago

int len = 80; printf("%" + len + "s");

Julian Kreuzer · Accepted Answer · 2021-09-30 17:08:27Z

0

This is not possible, the java output stream is so abstract that you basically don't know where the data is ending which you send to it.
Case scenario:
Somebody has set the output steam to a file where would there the right alignment be there?

answered Sep 30, 2021 at 17:08

Julian Kreuzer

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Comments

Pran Sukh · Accepted Answer · 2021-09-30 17:20:15Z

0

This could be possible with string formats.

Have a look at this link Read More.

answered Sep 30, 2021 at 17:20

Pran Sukh

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Comments

htamayo · Accepted Answer · 2021-10-01 18:33:32Z

this approach solve the problem:

class Result {
    public static void staircase(int n) {
        String myGraph = "#";
        String mySpace = " ";
        int numOfChars = 0;
        int i = 0;
        int j = 0;
        int k = 0;
        ArrayList<ArrayList<String>> gameBoard = new ArrayList<ArrayList<String>>();
        for(i=0; i<n; i++){
            gameBoard.add(new ArrayList<String>());
            numOfChars++;
            //fill of mySpace
            for(j=0; j<(n-numOfChars); j++){
                gameBoard.get(i).add(j, mySpace);
            }
            //fill of myGraph
            for(k=j; k<n; k++){
                gameBoard.get(i).add(k, myGraph);
            }
        }
        
        //iterate the list
        for (i = 0; i < gameBoard.size(); i++){
            for (j = 0; j < gameBoard.get(i).size(); j++){
                System.out.print(gameBoard.get(i).get(j));
            } 
            System.out.println();
        }        
    }
}

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