Question

I am pretty new to Java and I have a little problem with formatting a String. I have add “\n” for a new line after every 18th char and I have to split these new lines into array indexes, 13 lines for each index.

My code so far:

String[] strings = str.split("\n");
String result;
for (int i = 1; i < strings.length; i++) {
    i++;
    if ((i % 13) == 0) {
        result += strings[i];
    } else {
        result += strings[i] + "\n";
    }
}

It doesn’t work as it should, I tested a bit around bit I don’t know how to do this, could someone help me please?

Answer 1

You’re incrementing i twice in each loop – once in the increment expression of the for statement, and once inside the loop itself. This means i is always even, so i % 13 is probably not 0 when you expect it to be. In addition, the first index of an array is 0, so you would currently ignore the first element. As a more minor point, I would advise using a StringBuilder instead of appending Strings:

String[] strings = str.split("\n");
StringBuilder resultBuilder = new StringBuilder();
for (int i = 0; i < strings.length; i++) {
    String s = strings[i];
    if ((i % 13) == 0) {
        resultBuilder.append(s);
    } else {
        resultBuilder.append(s).append("\n");
    }
}
String result = resultBuilder.toString();