Write code to Count the occurrences of the substring in string s.
//package com.book2s; public class Main { public static void main(String[] argv) { String str = "book2s.com"; String sub = "o"; System.out.println(countOccurrencesOf(str, sub)); }/*from www. j a va2 s . c o m*/ /** * Count the occurrences of the substring in string s. * @param str string to search in. Return 0 if this is null. * @param sub string to search for. Return 0 if this is null. */ public static int countOccurrencesOf(String str, String sub) { if (str == null || sub == null || str.length() == 0 || sub.length() == 0) { return 0; } int count = 0; int pos = 0; int idx; while ((idx = str.indexOf(sub, pos)) != -1) { ++count; pos = idx + sub.length(); } return count; } }