How to populate a 2D array in Java using user input?

Question

I am trying to populate a two dimensional array in Java by using a user-inputted string. I have already got the string and I have figured out how to create the array. I am just having trouble figuring out how to get the values into the array. In case you are wondering, yes I have to use an array. Here is what I have so far:

    private static int[][] parseTwoDimension(String strInput)
        {
            int rows = 0; //number of rows in the string

            for (int i = 0; i < strInput.length(); i++)
            {
                if (strInput.charAt(i) == '!') //the ! is an indicator of a new row
                {
                    rows++;
                }
            }

            int[][] arr = new int[rows][]; //create an array with an unknown number of columns
            int elementCounter = 0; //keep track of number of elements
            int arrayIndexCounter = 0; //keep track of array index

            for (int i = 0; i < strInput.length(); i++)
            {
                if (strInput.charAt(i) != '!') //while not the end of the row
                {
                    elementCounter++; //increase the element count by one
                }
                else //reached the end of the row
                {
                    arr[arrayIndexCounter] = new int[elementCounter]; //create a new column at the specified row
                    elementCounter = 0; //reset the element counter for the next row
                    arrayIndexCounter++; //increase the array index by one
                }
            }
        /*
        This is where I need the help to populate the array
        */
        char c; //each character in the string
        int stringIndex = -1; //keep track of the index in the string
        int num; //the number to add to the array
        for (int i = 0; i < arr.length; i++)
        {
            for (int j = 0; j < arr[i].length; j++)
            {
                stringIndex++; //increment string index for next element
                c = strInput.charAt(stringIndex); //the character at stringIndex
                if (c == '!') //if it is the end of the row, do nothing
                {

                }
                else //if it is not the end of the row...
                {
                    String s = Character.toString(c); //convert character to String
                    num = Integer.parseInt(s); //convert String to Integer
                    arr[i][j] = num; //add Integer to array
                }
            }
        }
        return arr; //return a two dimensional array the user defined
    }

Any help is greatly appreciated :)

Slava · Accepted Answer · 2016-10-14 05:59:41Z

2

I've edited your code and posted it below. This is a general outline of how to solve it:

Use string.split("!") to separate your String by the delimiter '!'. This returns an array
Then, use string.split("") to separate the String into individual characters

Code posted below:

private static int[][] parseTwoDimension(String strInput)
{
    String[] rows = strInput.split("!");    
    int[][] arr = new int[rows.length()][];

    for(int i = 0; i < rows.length; i++)
    {
        String[] elements = rows[i].split("");
        int[] intElements = new int[elements.length];

        for(int j = 0; j < elements.length; j++)
        {
            intElements[j] = Integer.parseInt(elements[j]);
        }
        arr[i] = intElements;
    }
}

Let me know if this works. The string.split() function is really useful when parsing Strings into arrays

edited Oct 14, 2016 at 5:59

Slava

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answered Oct 14, 2016 at 3:46

awesome_sauce911

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1 Comment

Ethan Over a year ago

This worked perfectly! Thanks! I didn't even think to use string.split()

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