Why Doesn't My Substring Counting Algorithm Halt?

Why is the given algorithm not halting?

In the provided algorithm, an attempt is made to find the number of occurrences of a substring in a string. However, the algorithm is designed to continue until the last index of the substring in the string becomes -1. This condition will never be met because the last index is always being updated by adding the length of the substring to it. As a result, the algorithm will keep searching for the substring indefinitely, never terminating.

Using Apache Commons Lang for Substring Counting

An alternative approach to counting substring occurrences is to utilize the StringUtils.countMatches method from Apache Commons Lang. This method takes a string and a substring as arguments and returns the number of times the substring appears in the string. Using this method, the original problem can be resolved with the following code:

String str = "helloslkhellodjladfjhello";
String findStr = "hello";

System.out.println(StringUtils.countMatches(str, findStr));

This code outputs:

3

which correctly counts the occurrences of the substring "hello" in the string "helloslkhellodjladfjhello".

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