Print String as Triangle

public class Triangle {
	public static void main(String[] args) {
		String input = "abcdefghijklmnopqrstuvwxyz";
		int rowSize = 1, stringPosition = 0;
		for (int index = 0; index < (input.toCharArray().length / 2); index++) {
			String output = "";
			for (int i = 0; i < rowSize; i++) {
				output = output + (input.toCharArray()[stringPosition]);
				stringPosition++;
			}
			System.out.println(output);
			if (stringPosition >= input.toCharArray().length / 2)
				rowSize--;
			else
				rowSize++;
		}
	}

}