Print Java arrays in columns

Question

I\'m trying to format two arrays in Java to print something like this:

Inventory Number      Books                          Prices
--------------------------         


        

Answer 1

Without using any libraries, you need to determine the maximum length of each coloumn and append the needed space characters appropriately. For example like this:

/**
 * Determines maximum length of all given strings.
 */
public static int maxLength(int padding, String... array) {
    if (array == null) return padding;
    int len = 0;
    for (String s : array) {
        if (s == null) {
            continue;
        }
        len = Math.max(len, s.length());
    }
    return len + padding;
}

/**
 * Unifies array element lengths and appends 3 whitespaces for padding.
 */
public static String[] format(String[] array) {
    if (array == null || array.length == 0) return array;
    int len = maxLength(3, array);
    String[] newArray = new String[array.length];
    for (int i = 0; i < array.length; i++) {
        newArray[i] = array[i];
        while (newArray[i].length() < len) {
            newArray[i] += " ";
        }
    }
    return newArray;
}