It shouldn't be too difficult to pick up. C's design was influenced by ALGOL and Pascal, so the semantics and logical flow are going to be pretty familiar. You can get an overview of the differences between basic Pascal and basic C here.

But you tagged this as Delphi and you mentioned C++, which implies that you'll need information on OOP techniques. Try this article or this one, which compare object-oriented programming in Delphi with C++ and other languages. Both are a bit dated, but most of the basic information in them still applies today.

If you have any specific questions about language features, feel free to ask them here, and welcome to Stack Overflow!

Custom Scanner

Implement your own scanner. For example:

(limitations of this solution are mentioned in the comments)

private List<String> getResourceFiles(String path) throws IOException {
    List<String> filenames = new ArrayList<>();

    try (
            InputStream in = getResourceAsStream(path);
            BufferedReader br = new BufferedReader(new InputStreamReader(in))) {
        String resource;

        while ((resource = br.readLine()) != null) {
            filenames.add(resource);
        }
    }

    return filenames;
}

private InputStream getResourceAsStream(String resource) {
    final InputStream in
            = getContextClassLoader().getResourceAsStream(resource);

    return in == null ? getClass().getResourceAsStream(resource) : in;
}

private ClassLoader getContextClassLoader() {
    return Thread.currentThread().getContextClassLoader();
}

Spring Framework

Use PathMatchingResourcePatternResolver from Spring Framework.

Ronmamo Reflections

The other techniques might be slow at runtime for huge CLASSPATH values. A faster solution is to use ronmamo's Reflections API, which precompiles the search at compile time.