In C: Implement a function char *reverse words(char *str) that accepts a string and reverses the word ordering within the string. The characters within the words are not reversed. The function will allocate space to store the string with reversed word order. You can modify the input string if necessary.

Sample input and expected output:

Hello World -> "World Hello" -> "" HeyYou -> "HeyYou"

What is the question? -> question? the is What

It is what it is. -> is. it what is It