these words were uppercase, but strtolower() made them lowercase!
str_word_count will count the number of words in a sentence. In the sentence used, there were: 4 words.
Predefined Functions are a set of over 1000 functions included in PHP. Opposed to user defined functions, there is no need for the user to set them. They generally consist of frequently used functions so that users won't have to repeatedly code them in different projects.